Preliminary Program Plan FY2005

O National Radio Astronomy ProgramPlan Observatory

FiscalYear-2005

NATIONAL RADIO ASTRONOMY OBSERVATORY

October 13, 2004

The National Radio Astronomy Observatory is a facility of the National Science Foundation operated by Associated Universities Inc. Table of Contents

Mission Statement...... 1

1. Introduction...... 3

2. Science Programs in FY2005...... 7 Overview...... 7 Cosmology and the Early Universe ...... 8 Radio Galaxies, Quasars, Active Galactic Nuclei, and Gamma Ray Bursts ...... 11 Nearby Galaxies and the Galactic Center ...... 16 Molecular Clouds, Star Formation, and Galactic Structure...... 20 Pulsars and Other Radio Stars...... 24 Solar System; Geophysics...... 26

3. ALMA Construction ...... 29 Project Overview ...... 29 Science Objectives...... 30 Technical Objectives...... 31 Project Status ...... 33 Program FY2005...... 40

4. ALMA Operations ...... 45 Overview...... 45 North American ALMA Science Center...... 45

5. Expanded Very Large Array...... 51 Overview...... 51 Phase I...... 52 Planned Activities for FY2005 ...... 55 Phase II...... 58

6. NRAO Facilities...... 59 Green Bank Telescope ...... 59 Very Large Array...... 77 Very Long Baseline Array...... 88

7. Central Development Laboratory ...... 99 Cooled HFET Development ...... 99 MMIC Development...... 101 Millimeter-Wave Receiver Development...... 103 Electromagnetics...... 104 Budget ...... 105

Table of Contents

8. NRAO Science & Academic Affairs ...... 107 Introduction...... 107 The Research Staff of the NRAO ...... 107 Library and Archives ...... 108 Educational Programs ...... 110

9. Observatory Computing...... 113 Overview...... 113 Software Development...... 113 Project-Based Software Development ...... 113 Data Storage and Retrieval ...... 116 Central Computing Services ...... 119

10. Education and Public Outreach...... 125 Overview ...... 125 New Initiatives...... 125 ALMA ...... 127 NRAO Website ...... 128 NRAO Brochures...... 128 Astronomical Community...... 129 Media Relations ...... 132 Visitors Center ...... 133 Education ...... 134

11. Observatory Management...... 137 Overview...... 137 Program Office...... 139 Business Services...... 147 Environment, Safety, and Security ...... 148 Human Resources ...... 150

12. Initiatives and Other Activities ...... 155 New Initiatives...... 155 Charlottesville Facilities ...... 159 Spectrum Management ...... 160

13. Impact of Alternate Funding Levels ...... 163 Introduction...... 163 The Need for the Mission Requirement Level...... 163 The Adequacy of the Mission Requirement Level ...... 164 The Impact of Funding at the President’s Request Level...... 165

14. FY2005 Preliminary Financial Plan...... 169

Table of Contents

Appendix A - Scientific Staff Research Activities ...... 177

Appendix B - Research Staff ...... 203

Appendix C - Management Staff ...... 207

Appendix D - Committees ...... 209

Mission Statement

The mission of the National Radio Astronomy Observatory (NRAO) is to design, build, and operate large radio telescope facilities for use by the scientific community; to develop the electronics, software, and other technology systems that enable new astronomical science; to support the reduction, analysis, and dissemination of the results of observations made by the telescope users; to foster the user community; to support the development of a society that is both scientifically and technically literate through educational programs and public outreach; and to support a program of staff scientific research that enables leadership and quality in all these areas.

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1. Introduction

Overview

This is an exciting and challenging time at the National Radio Astronomy Observatory (NRAO). Through the Atacama Large Millimeter Array (ALMA) project and the first phase of the Expanded Very Large Array (EVLA) project, the NRAO is involved in designing and building new centimeter, millimeter, and sub-millimeter wavelength research facilities that will open scientific frontiers for scholars and students. Observatory personnel also continue to meet the challenges of developing new capabilities and operations modes for existing NRAO facilities: the scientific productivity of the Robert C. Byrd Green Bank Telescope (GBT) continues to improve at a rapid rate; the Very Large Array (VLA) continues to be one of the world’s most productive scientific instruments; and the Very Long Baseline Array (VLBA) continues to probe astrophysical domains at sub-arcsecond resolution.

The details of the Observatory’s numerous Fiscal Year (FY) 2005 initiatives and on-going programs supported by the Missions Requirement Level (MRL) budget are described in the following chapters of the NRAO Program Plan and include the following:

Next Generation Observing Facilities

• FY2005 will be a year of extraordinary accomplishment for the North America ALMA Project. Early in the fiscal year, responsibility for management of the North America ALMA Project will smoothly transition from NRAO Director K. Y. Lo to Adrian Russell, who will join the NRAO staff from his most recent post as Director of the United Kingdom Astronomy Technology Centre in Edinburgh, Scotland. Dr. Russell will effectively lead the North America ALMA Project as each of the project’s Integrated Product Teams (IPTs) achieves numerous critical milestones. The ALMA Site Development IPT will complete construction of the contractor’s camp at the Operations Support Facility (OSF) and begin construction of the Array Operations Support (AOS) civil infrastructure. The production-antenna procurement contract will be executed early in the new fiscal year and the Pre-Production Design Review will take place soon thereafter. The first Front-end Subsystem production cartridge for the 1 mm band will be completed in FY2005, as will the detailed design of the production Back-End modules. Significant progress will be made on the ALMA Correlator’s first quadrant at the NRAO Technology Center (NTC), and the Observatory’s ALMA software development efforts will move strongly forward. The Systems Engineering and Integration IPT will integrate the prototype Back End, Local Oscillator (LO), Correlator, and Computing sub-systems and complete planning for Systems Integration in Chile. The Science and Imaging IPT will make significant progress in the development of calibration plans and algorithms for ALMA science data products. The Observatory’s detailed FY2005 Program Plan for ALMA Construction and ALMA Operations are described in Section 3 and Section 4, respectively.

• FY2005 will be the fourth year of the Observatory’s work on the first phase of the Expanded Very Large Array (EVLA) project. By the end of FY2005, the NRAO will have outfitted five of the array’s twenty-seven antennas to the EVLA design, and the new, wide-band L, C, and Ka- band receivers will be installed. Routine scientific observing will commence with EVLA antennas in the first quarter of FY2005, and critical electronic and mechanical components will be ordered in bulk. Significant progress will also be made on planning for EVLA operations, with careful attention to the transition from VLA to EVLA operations. The Observatory’s FY2005 Program Plan for the EVLA project is described in Section 5.

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1. Introduction

New Capabilities for Scientific Discovery

• The GBT offers an impressive instrumentation suite for observers, including nine receivers that operate from 290 MHz to 50 GHz and multiple detector back-ends. A key FY2005 strategic goal will be to achieve efficient GBT scientific performance at 3 mm wavelength. The Observatory will also increase the amount of GBT observing time and will commission several major instruments, such as the Ka-band receiver and its associated Millimeter-wave Down-converter. The study phase of the azimuth track program will conclude early in FY2005 and will be followed by a panel review, with contracts let for the requisite repair work by mid-year.

• In this era of multi-wavelength astronomical research, the demand on the powerful VLA for coordinated observations with space missions is steadily increasing. The NRAO is responding to this need by providing ~ 200 hours of VLA time in support of joint VLA / Chandra proposals and by entering into discussions with the Spitzer Observatory regarding the possible terms and conditions of a similar joint VLA / Spitzer program. The transition from VLA to EVLA operations will receive significant attention in FY2005, with the Observatory working hard to assure minimal impact on the array’s high scientific productivity. Despite the complexities of this transition, the NRAO will experiment with dynamically scheduling the VLA. During FY2005, the Observatory will also complete the first phase of a program to develop a new, compact water- vapor radiometer based on MMIC technology.

• In FY2004, the NRAO and Haystack Observatory led a community-wide effort to develop a science and technology roadmap for U.S. VLBI over the next five years. This committee’s report, “Mapping the Future of VLBI Science in the U.S.,” is the basis for the Observatory’s forward- looking VLBI program plan in FY2005. To achieve better sensitivity and higher operational efficiency, the current VLBA tape-based recording and playback systems are being replaced as quickly as possible by hard-disk systems. Observatory staff continue to engineer changes to VLBA operations that make observing easier and more scientifically productive. Proposals for the High Sensitivity Array (HSA) have their first observations scheduled for early in FY05. The HSA capability opens promising new avenues for scientific discovery.

A sample of the innovative and forward-looking scientific programs that will be conducted on NRAO instruments by visiting scientists, students, and NRAO staff is described in Section 2. These programs include using the GBT to improve our understanding of small-scale anisotropies in the Cosmic Microwave Background, possibly detecting galaxy cluster formation at high redshift and improving our understanding of large-scale structure formation in the Universe. Astronomers will also seek evidence that the fine-structure constant varies with the age or size of the expanding Universe by using the GBT to observe narrow, redshifted OH and HI absorption lines in distant astronomical sources. Astronomers will continue to use the VLA to probe the complex and interesting physics of jets in extragalactic radio sources. Other innovative observational programs will focus on the physics of gravitational lenses, ultra- low-luminosity AGN candidates, radio supernovae, and the three-dimensional structure of gamma-ray blazer jets. Astronomers will also use the sensitivity and resolution of the VLA to investigate the detailed structure and motion of gas in nearby Virgo Cluster galaxies, and study the low-frequency structure of the Galactic Center. Joint VLA / Chandra observations will examine in unprecedented detail the faint nuclear source of M31. The GBT’s high sensitivity, wide bandwidth, and innovative instrumentation will be used to discover and study pulsars in globular clusters. Observers will also use NRAO radio telescopes to study relatively local astronomical objects, including Mercury, Venus, Titan, Uranus, and the Sun. NRAO

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1. Introduction

staff research programs are detailed in Appendix A. The research interests of every NRAO staff member participating are summarized in Appendix B. A detailed description of the Observatory’s FY2005 initiatives and programs for the GBT, VLA, and VLBA is given in Section 6, “NRAO Facilities.”

The Central Development Laboratory (CDL) is a vital organizational component of the NRAO. The CDL personnel design and fabricate the electronics instrumentation on all NRAO telescopes, including ALMA. In FY2005 the engineers, scientists, and technicians at the CDL will continue their development of unique cooled HFET (heterostructure field-effect transistor) amplifiers, millimeter-wave receivers, MMIC devices, and the wide-band components that serve CDL-developed mixers and amplifiers. Detailed plans for these efforts are given in Section 7.

The Division of Science and Academic Affairs (DSAA), formed in mid-2003 to provide a more coherent framework for the Observatory’s scientific and academic activities, is described in Section 8. Fostering closer ties between the NRAO and the astronomical community is a high priority for the Observatory’s scientific staff. The enhanced 2005 Jansky Fellowship Program provides outstanding research opportunities for young astronomers, on par with the Hubble, Chandra, and Spitzer Fellowship Programs. Jansky Fellowships can be held at any U.S. institution or any NRAO site. In consultation with its user community, the NRAO has also initiated a program to support astronomical research at the GBT by graduate and undergraduate students at U.S. universities. This program offers substantial financial support and strengthens the proactive role of the Observatory in training new generations of telescope users. The Observatory has seen excellent community response to this GBT program and hopes to initiate a similar program in FY2005 for the VLA and VLBA. Through the enhanced NRAO Visitors Program, the Observatory also encourages Ph.D. scientists and engineers in radio astronomy and related fields to visit its facilities. The terms of a visit are negotiable, ranging in duration from weeks to months. The purpose of a visit can be interaction with NRAO staff, summer research, or a sabbatical.

Observatory Computing is described in Section 9. These personnel and programs provide an optimum computing and network environment for NRAO telescope users, for the operation of the Observatory’s instruments, and for the development of new facilities. The telescope-oriented tasks previously included in Data Management have been assigned to local site managers, and the Interferometry Software Division and Single Dish Software Division have been created.

The NRAO Education and Public Outreach (EPO) office has ambitious plans for improving public awareness and understanding of astronomy and of the NRAO in FY2005, including two new initiatives endorsed by the Visiting Committee (Section 10). The NRAO Legacy Imagery initiative will develop an in-house capability to process radio imagery into compelling visual imagery of astronomical objects. The Science Museum Outreach initiative is a cooperative venture with the Space Telescope Science Institute that will bring NRAO science and press releases to major museums and planetariums in the United States. Other NRAO EPO programs in FY2005 will focus on ALMA, re-vitalizing the Observatory’s brochures, outreach to the astronomical community, and a broad range of education programs.

Section 11 is devoted to Observatory Management, including the Director’s Office, key intra-Observatory communications initiatives, the Program Office, Human Resources, Business Services, and Environment, Safety, and Security. The Observatory’s FY2005 Program Office initiatives will enable the efficient capture and dissemination of more quantitative and detailed programmatic data and metrics. The Program Office will quickly build capability throughout FY05, and all NRAO projects and programs will use a PMCS solution by the end of FY05. As these capabilities come on-line, the Observatory will strengthen and streamline its program reporting, metrics, assessment, and overall management capabilities.

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1. Introduction

Members of the Observatory management staff are listed in Appendix C.

NRAO efforts devoted to New Initiatives are described in Section 12, along with plans for the Observatory’s Charlottesville facilities and the FY2005 program for Spectrum Management.

The NRAO Program Plan for FY2005 is based on the management of the Observatory according to a comprehensive Work Breakdown Structure (WBS) that has been designed to track and account for every Observatory activity. Chapter 14 shows the distribution of personnel and funding according to WBS activity. Management by the WBS allows the full scope of Observatory activities to be assessed, the costs to be properly established, and the interrelations between activities to be readily visualized. It also has the advantage of correctly presenting the Observatory organization as a single, centralized, management structure.

Finally, a major goal for 2005 is the establishment of better communications with the astronomical community, increased involvement of the community in strategic planning, and increased support for university-based radio astronomy groups. The astronomical community members who have generously served on the Observatory’s Program Advisory Committee, EVLA Advisory Committee, Visiting Committee, and Users Committee (Appendix D) have provided vital feedback and input to the Observatory. External advice for ALMA is provided by members of the ALMA Scientific Advisory Committee, the ALMA Management Advisory Committee, and the ALMA North American Science Advisory Committee. These inputs have had a major influence on the nature and scope of the initiatives and programs proposed in this FY2005 Program Plan.

The funding needed in FY2005 to support the initiatives described in the Program Plan constitutes the Mission Requirements Level (MRL). Unfortunately, the President’s Request Level (PRL) FY2005 budget of $47.41M for NRAO operations is $7.59M less than the $55.00M required for the mission. Because of the large difference between the Mission Requirements Level and President’s Request Level budgets, this FY2005 Program Plan is written to the Mission Requirement Level budget, and the ramifications of a reduction to the President’s budget, should that be required, are described in Section 13. The opportunity to realize the benefits of the investments in planning, design, and program development at the NRAO over the past decade is achievable only at the Mission Requirements Level.

The NRAO sees the challenges of the present as necessary and welcome steps toward the scientific opportunities of the future. The Observatory’s people are proud of what they have accomplished and confident of their ability to design, operate, and maintain the facilities demanded by the extraordinary scientific enterprise that is modern astronomy.

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2. Science Programs in FY2005

Overview

The scientific investigations which are planned for NRAO telescopes in FY2005 span the range of forefront research topics in astronomy and astrophysics. This section describes a sample of proposals from the entire astronomical community, and a closer look at NRAO staff research is provided in Appendix A. Some highlights:

(1) Irregularities in the Cosmic Microwave Background (CMB) radiation trace the clumping of mass to form galaxies and clusters of galaxies in the early universe. Sensitive observations with the GBT will enhance measurements of these irregularities by removing contamination from intervening radio galaxies and quasars.

(2) The first supermassive black holes were formed when the universe was less than one billion years old and are visible now as high-redshift (z > 6) quasars. VLA continuum images of five quasars with the highest known redshifts will address the question of whether the first supermassive black holes and galaxies of stars formed at the same time.

(3) Water megamasers like those in the nearby galaxy NGC 4258 have been discovered in more distant galaxies by the GBT and may be imaged with sub-milliarcsecond resolution by the VLBA. Such an image can yield the mass of the nuclear black hole, an accurate geometrical distance to the galaxy, and a more reliable estimate for the Hubble constant.

(4) The Swift gamma-ray satellite will soon be launched to detect gamma-ray bursts (GRBs) from collapsing stars visible throughout the universe. A major VLA/VLBA program will follow up new GRBs to image their relativistic jets, thereby testing models for the explosive collapse and the evolution of massive stars over cosmological time scales.

(5) The VLBA recently detected the central compact object, either a neutron star or a black hole, formed 18 years ago during the supernova SN1986J in the nearby galaxy NGC 891. It will follow the evolution of this, the youngest known collapsed star.

(6) The sensitivity of the GBT permits pulsar timing with exquisite accuracy. Timing observations will test general relativity in binary pulsar systems, constrain the level of low-frequency gravitational radiation in our Galaxy, and measure the mass distributions of globular clusters. The GBT will perform the most sensitive possible high-frequency search for pulsars in the star cluster surrounding the black hole at the Galactic Center. If detected, such pulsars will be used to characterize the black hole itself.

(7) The VLA+Pie Town will image the protoplanetary disk orbiting the young star TW Hydrae with a resolution of two astronomical units, enough to detect a possible central hole and yield insights into the formation of planets.

(8) The rotation rates of Mercury and Venus will be determined with extraordinarily high accuracy to measure core-mantle coupling of both planets. These results will be derived from speckle observations of radar echos by the GBT and NASA's Goldstone antenna.

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2. Science Programs in FY2005

(9) The GBT will monitor all 27 Global Positioning System (GPS) satellities with the highest possible signal-to-noise ratio in order to characterize small signal distortions that might affect the next generation of aircraft landing systems.

Cosmology and the Early Universe

The accuracy of measurement of small-scale anisotropies in the Cosmic Microwave Background is currently limited by contamination of the data by the foreground of discrete radio sources, particularly at multipoles l > 2000 where the Sunyaev-Zel'dovich (SZ) effect from clusters between us and the last scattering surface are thought to contribute a significant signal. The GBT will be used to observe several hundred sources at 30 GHz, selected from 1.4 GHz surveys, in order to estimate their spectral indices and the general properties of the high-frequency radio source population. Specifically, the GBT will be used a) to “veto” the deletion of many pixels now excluded from CMB analyses due to the presence of 1.4 GHz sources (most of these are thought to be unimportant at 30 GHz but GBT data are needed to conclusively show which ones do matter); and b) to better constrain the contribution of the “residual source” statistical correction. Some of the best constraints at l > 2000 currently come from the Cosmic Background Imager, an experiment operating in the 26 to 36 GHz range. Including systematic uncertainties due principally to discrete sources, the CBI sees a bandpower of 355 ± 120 µK2, which in a full maximum likelihood analysis turns out to be ~2 sigma in excess of the expected level of intrinsic anisotropy (~85 µK2), or about 2.9 sigma above zero power. We expect GBT results to reduce the uncertainty from 120 to about 90 µK2 through reclaiming CBI data and reducing the uncertainty in the statistical correction. Equally important, direct 30 GHz measurements with the GBT would conclusively resolve concerns which some in the CMB community hold in regard to residual source contamination. This work could make the first clear detection of cluster formation at high redshift through the SZ and thereby further improve our understanding of the history of large scale structure formation in the Universe. This work and future work like it will also have implications for the next generation of CMB polarization experiments, which will require far better understanding of foregrounds than presently exists in the microwave regime.

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Figure 2.1. Composite of data from several cosmic background anisotropy measurements showing the angular power spectrum of the background. The multipole moment l is inversely related to the angular scale. GBT measurements of faint sources at 30 GHz will reduce the uncertainties at l >2000.

It has been proposed that spinning dust grains in interstellar clouds might produce weak microwave emission which would be a major contaminant of Cosmic Microwave Background experiments. The GBT will be used to map several regions of apparently anomalous continuum emission at two frequencies to determine its intensity and spectrum. The data will be able to discriminate between free-free and spinning dust as the source of the continuum emission.

Two surveys will examine the properties of faint radio sources. In one, a VLA Large Program will be conducted in FY05 in conjunction with the COSMOS survey being carried out at multiple wavebands. The COSMOS survey is aimed at studying galaxy and black-hole evolution at redshifts between 0.5 and 3, when the peak of galaxy formation is thought to have taken place. COSMOS is based on an HST Treasury project accompanied by VLT spectroscopy of 100,000 sources over a 2 deg2 field. This field is large enough that cosmic variance should not cause biases, an important consideration in making inferences about the early universe from small fields. The VLA observations will include 240 hours of deep mosaicing in the A configuration, which may detect 5000 star-forming galaxies, and 24 hours of C-configuration observing, which will enable detection and removal of large radio galaxies that would contaminate the sample. The VLA data will test at high redshifts the famous far-infrared/radio correlation which is known to be very tight in the local universe. This correlation allows the radio samples and flux densities to be used as uniquely sensitive tracers of the cosmic star-formation rate and its evolution with time. Unlike the optical data, the radio data are not degraded by dust absorption, so they don't miss star formation in obscured galaxies.

The second is the VLA Low-Frequency Sky Survey (VLSS), a 74 MHz survey complementing the much- used 1400 MHz NRAO VLA Sky Survey (NVSS). The VLSS will use more than 600 hours over several B-configuration cycles to cover the sky north of -30 deg declination with 80 arcsec resolution and detect

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~105 sources stronger than 500 mJy at 74 MHz. The VLSS is uniquely sensitive to steep-spectrum radio sources such as radio galaxies, quasars, relic and halo sources in galaxy clusters, and star-forming galaxies, and it should even detect the continuum emission from about 100 pulsars. Specific scientific goals include discovering the first radio galaxies and large mass concentrations forming near the epoch of reionization, studying interactions between old radio lobes and the hot X-ray gas in galaxy clusters, discovering pulsars whose pulsed emission was missed by traditional searches for pulses, modeling the cosmological evolution of radio sources whose emission is nearly isotropic and unaltered by Doppler boosting, and disentangling the superposition of sources along complex lines of sight in our Galaxy via the contrast between nonthermal emitters and free-free absorbing HII regions. Figure 2.2 is a small VLSS subimage showing a number of faint radio galaxies and quasars. The VLSS is being made as a service to the astronomical community, and the principal data products are being released to the public as soon as they are produced and verified.

Figure 2.2. Grey-scale representation of a 3˚ x 3˚ portion of one of the VLSS survey fields. The faintest detectable source has a flux density of approximately 0.5Jy.

George Gamow originally proposed that the fine-structure constant varies with the age or size of the expanding universe, and his suggestion has been repeated in modern quantum theories intended to unify all forces of nature. There is tantalizing but not yet convincing evidence for such a variation from optical observations of distant astronomical sources. Radio observations of redshifted OH and HI absorption lines are potentially far better indicators because radio spectrometers have higher frequency resolution and the radio lines are intrinsically narrower. The GBT will be used to measure the fine- structure constant by comparing the velocities of OH and HI lines from distant objects. In one experiment, the lines will be measured from a number of red quasars at redshifts between 0.5 and 3.5. In another experiment the OH and HI lines will be measured from a set of known damped Ly-" systems

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with redshifts ranging from z=0.1 to z=3.4. The results will give values of the fine-structure constant that are more precise by an order of magnitude than the optical data and can test for possible changes in the fine-structure constant over 80% of the history of the Universe.

Emission lines from the molecule CO have been detected from a number of objects at redshifts greater than one, implying the presence of large amounts of dense star-forming molecular gas in these sources, presumably in their nuclear starburst regions. The GBT will be used to measure an accurate CO spectrum from HR10, a galaxy at z=1.44, which is of special interest because it appears to have molecular gas spread over a region tens of kiloparsecs in size. It may be a galaxy in formation. The CO spectrum from a large rotating disk is expected to exhibit characteristic velocity structures that will distinguish it from more centrally condensed systems.

The discovery of absorption from molecules at significant redshifts has opened up new opportunities to study the interstellar medium of distant galaxies. The GBT will observe a set of transitions of ammonia in an object at z=0.89, a lookback time of 7 Gyr. These data will give information on the physical conditions in this most distant molecular environment which can be studied in detail.

A VLA program will be carried out to achieve sensitive, high-resolution continuum imaging of five of the highest redshift quasars known, at z~6. The presence of quasars at this high redshift, in the first billion years since the expansion of the Universe began, implies that massive black holes had already agglomerated very early in the era of galaxy formation. The primary purpose of the VLA project is to study the radio-to-optical spectral energy distributions and hence address the question of contemporaneous formation of massive black holes and spheroidal galaxies.

Radio Galaxies, Quasars, Active Galactic Nuclei, and Gamma Ray Bursts

Because of the need for high angular resolution, most of the research on these objects is conducted with the VLA and VLBA, where imaging on angular scales of arcseconds and milliarcseconds can be achieved. The GBT is used to survey for interesting objects, and in support of long-baseline interferometry programs, especially where its large aperture can be decisive.

Emission in the H2O line from a “megamaser” in a galactic nucleus provides information on the nuclear torus and black-hole mass, and may yield a precise measurement of the distance to the galaxy independent of the usual distance ladder. The first step in this promising research area is to identify galactic nuclei that show maser emission. For this, the GBT is very powerful. It will continue to search for H2O megamasers in a sample of quasars at z>0.4, the minimum distance at which deviations from the Hubble law are observed in supernova experiments.

Once such objects are identified, an attempt can be made to image them with the VLBA, usually in combination with other large telescopes. In FY05 it is proposed to observe at least three weakly active galaxies containing H2O megamaser emission. The relatively weak maser emission was discovered recently, either with the GBT or with the 70-m NASA tracking antenna in Australia. Regions of maser emission that are separated in velocity by ~1000 km/s or more provide the apparent signatures of rapidly rotating molecular disks surrounding central black holes. Previously, the VLBA was used to image a similar maser disk in NGC 4258, providing an accurate measurement of the central black-hole mass and a direct measure of the galaxy distance. The primary goal of the new programs will be to determine whether similar, relatively simple rotating disks may exist in several more megamaser galaxies. This

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would lead to measurements of the central black-hole masses with much more accuracy than is possible in other galaxies at optical wavelengths, and also could lead to further monitoring observations that would provide accurate distance measurements and thus an independent calibration of the Hubble relationship for the expansion of the Universe.

Hot, highly ionized gas at a temperature of more than a million K is abundant in many galaxies and clusters. It may be the dominant form of baryons in the local universe. The GBT will be used to search for the hyperfine transition of NVII, an analog to the 21 cm line of HI, from this hot gas. Detection of the line would give a new probe of density, temperature, and pressure in the hot gas for a range of astronomical objects.

One of the more interesting discoveries of extragalactic astronomy over the past few years has been that certain clusters of galaxies seem to have “holes” in their X-ray emission and that these X-ray cavities are related to the emergence of radio jets into the intracluster medium. X-ray cavities are formed by the pressure from radio lobes on “bubbles” displacing the hot gas; X-ray emission corresponds to a lack of radio emission. The low-frequency capability of the VLA, particularly at 327 MHz, is crucial for studying the old, steep-spectrum radio lobes in X-ray clusters. In FY05 a number of additional clusters with good X-ray images will be imaged with the VLA to determine whether they still are being fed by radio jets. Measurement of the spectral indices of the radio lobes, together with the buoyancy ages of the X-ray emission, can be combined to determine the magnetic field strengths in the radio bubbles. This in turn may lead to a determination of whether the primary support for the radio bubbles is the hot X-ray emitting gas or the intracluster magnetic field.

One of the primary scientific goals for constructing the VLA in the late 1970s was to understand the physics of jets in extragalactic radio sources. In FY05 the VLA will continue its history of exquisite imaging of radio jets to address some new questions. For example, in the nearby radio galaxy Centaurus A previous VLA and Chandra imaging has shown that some of the bright X-ray knots coincide with weak radio knots (see the combined radio/X-ray image in Figure 2.3). The spatial coincidence implies that the X-ray emission is likely to be synchrotron emission from very high energy electrons, which have emitting lifetimes measured in years. Using the VLA + Pie Town link at 8.4 GHz, a resolution of 2 pc will be achieved on the jet of Cen A. Continued monitoring of this jet is expected over the next several years in order to determine the relative evolution of the radio and X-ray emission, as well as the motions in the apparently subluminal jet. Another radio galaxy, 3C 296, will be imaged in multiple VLA configurations. The image will be combined with recent models for relativistic jets to determine the three-dimensional distributions of velocity, radio emissivity, and magnetic fields, as well as to measure the external entrainment of material at varying distances from the galaxy nucleus. The relatively nearby superluminal source 3C 120 continues to provide interesting constraints on jet physics, and it will be monitored at 1.7 GHz with the VLBA.

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Figure 2.3. Composite radio (red) and X-ray (blue) image of the inner portion of Cen A. The jet is about 35 arcseconds (700 pc) long. The coincidence of bright X-ray knots and weak radio kots implies that the X-rays arise from synchrotron emission.

The radio galaxy Virgo A is associated with M87, the bright central galaxy in the nearby Virgo cluster. In 2003 a jet knot called “HST-1,” located only 0.8 arcseconds from the galaxy nucleus, flared by factors of 10 or more at X-ray, optical, and radio wavelengths. High-frequency radio imaging of this knot will be carried out by the VLA in its A and B configurations in order to study the knot evolution and compare it with the results at other frequencies. The relative time lags of the rise and decay of the emission in different bands severely constrain models for the flare sources. In addition, the decay of the light curve can be used to determine whether expansion losses or synchrotron losses dominate; expansion losses will be independent of observing frequency, whereas synchrotron losses will depend strongly on particle energy (and observing frequency). The VLBA will be used along with the VLA to measure the knot flux at lower frequencies, where the VLA cannot resolve the knot from the strong nucleus. In fact, after the VLA antennas are changed to a smaller configuration in April 2005, only the VLBA will be capable of imaging the knot and resolving it from the rest of the radio source.

One of the fundamental discoveries in extragalactic astronomy over the last decade has been that most galaxies with significant spheroidal components (either elliptical galaxies or spirals with bulges) appear to contain central black holes, sothat the formation of those black holes must be closely coupled to the formation and evolution of the spheroidal components. Studies of such objects generally have been restricted to black-hole masses of at least a few million solar masses because the gravitational influence of less-massive black holes is extremely difficult to detect. A VLA program will search for weak active galactic nuclei (AGNs) in a sample of 20 galaxies with black holes that are thought be less than a million solar masses, based on data from the Sloan Digital Sky Survey. The AGNs in these objects appear to

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radiate near the Eddington limit of their central black holes, and radio upper limits from the FIRST survey show that they have weaker radio sources than most nearby active galaxies. The radio powers and structures will be investigated to see if these objects with low-mass black holes differ systematically from galaxies with higher mass black holes, and thus if the accretion and jet-formation processes are systematically different as well.

Theory predicts that gravitational lenses should produce an odd number of images of the background source. However, most systems found to date have an even number of images because the central image is highly de-magnified by the lens. The central images are of considerable interest because they are probes of the mass distribution in the central few hundred parsecs of the lensing galaxies. Two VLBI programs will attempt to study the elusive third images produced by gravitational lenses. One program will perform multi-frequency VLBA imaging of a weak radio source in J1632-0033 that may be a central image; its origin is in doubt because its low-frequency spectrum is inconsistent with the two brighter images, contrary to the fact that gravitational lensing should be achromatic and preserve spectral information. For J1632-0033 it has been hypothesized that the central image is free-free absorbed by the intervening galaxy, accounting for its relative weakness at 1.7 GHz. Multi-frequency VLBA imaging will test this hypothesis and also could lead to a confirmed detection of ionized material in the core of an apparently inactive distant galaxy. In another object, B1030+074, the High Sensitivity Array will be used to make a very sensitive search for a central image coincident with the lensing elliptical galaxy. This object has been chosen because it is the brightest two-image system coincident with an elliptical galaxy, and thus it should have the least demagnification and would provide a probe of the mass distribution in the inner region of a distant elliptical.

A Chandra X-ray survey of optically inactive galaxies has found five ultra-low-luminosity AGN candidates that have X-ray luminosities of only 10-10 to 10-7 times the Eddington limits of the central black holes. Typically, low-luminosity AGNs are relatively loud in the radio, indicating different accretion and emission processes than in powerful AGNs, which radiate near their Eddington limits. For this sample of even lower-luminosity objects, sensitive VLA imaging will be used to determine whether any radio sources are centrally located and are AGNs rather than X-ray binaries. If central radio sources are detected and their identification as counterparts of AGN confirmed, the radio/X-ray ratios will be determined and compared with the generic low-luminosity AGNS. This will show whether the trend of radio loudness continues in even lower-luminosity objects, and whether the ultra-low-luminosity objects are controlled by the same physical processes as their somewhat more powerful cousins.

The VLBA is being used at frequencies from 1.6 - 86 GHz to discern the structure of gamma-ray blazar jets by measuring variation in component proper motion, magnetic field structure, and foreground effects (e.g., Faraday rotation). Typically, the observations below 10 GHz cannot adequately resolve the transverse and longitudinal structure of these jets, while higher-frequency observations lack sufficient surface-brightness sensitivity to see any but the brightest of the jet components, since these fade quickly as they move out. Thus it is difficult to develop a complete geometrical and evolutionary model of the jet material and the shocks which move through the jets without data from the widest possible range of frequencies. Together with isolation of stationary components (including the observed “core” at each frequency), the measurement of component motions (apparent velocities and accelerations) over greater distances along the jet should yield clues about the jet structure in three dimensions. The high level of aberration in these well-aligned jets should show polarization degree and orientation effects which correlate with the geometrical picture and thus strengthen the models. Better geometrical models of these jets will enable better estimates of optical and Faraday depth, magnetic field order, gamma-ray emission origins, dependence of jet properties on optical identification, etc.

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The MOJAVE project (Monitoring Of Jets in Active Galaxies with VLBA Experiments) will continue throughout FY05. This will be the second 18-month cycle of this Large VLBA Program, which involves multiple-epoch 15-GHz imaging observations to study the relativistic jets in 133 quasars and AGN. The monitoring intervals are tailored to the individual sources and range from a few months to more than a year. Primary science goals include understanding the detailed physics of individual sources and evaluating the statistics of superluminal speeds and other structural changes. MOJAVE monitors a sample of sources considerably larger than any previous effort of this type, at more regular intervals, and for the first time includes full polarization information giving new insight into the physics of relativistic jets.

MOJAVE observations have thus far established a strong connection between the polarization properties of the jets and their optical line strength, which are both likely dependent on total jet power. The polarization vectors tend to follow the curvature in the jets, implying streaming rather than ballistic flow. Further evidence for this streaming motion comes from previous multi-epoch VLBA observations of the relativistic jet flow which shows features moving along the curved jet trajectory. The new MOJAVE polarization observations show that the gradient direction of the fractional polarization is precisely aligned with the electric vectors and the direction of the local jet flow, thus providing strong evidence for ordered, transverse shocks in AGN jets.

In last year’s Program Plan we anticipated a program of follow-up observations to gamma-ray bursts discovered by the Swift satellite, which was to have been launched midway through FY04. Instead, the launch has been delayed until no earlier than October 2004. A VLA Large Proposal has been accepted to follow up on the new gamma-ray bursts of special interest, such as those in the most nearby and most distant galaxies, as well as those clearly associated with supernovae, once Swift becomes operational. In light of recent new discoveries regarding the overall calorimetry and relativistic jet expansion, we anticipate several fruitful years for the VLA observing Swift-discovered gamma-ray bursts. In addition, we expect that there will be VLBI follow-up observations on nearby gamma-ray bursts, at z<0.2 or so. The burst 030329 took place in March 2003 in a relatively nearby galaxy at z=0.17 and was observed with the VLBA and most of the world’s large radio telescopes later in the year. Model-fitting shows that the VLBI source was slightly resolved, indicating a size consistent with relativistic-jet models. Imaging of any closer and stronger burst, as one might expect to detect with Swift once or twice per year, could provide a dramatic test of models for the explosion and evolution of gamma-ray bursts at cosmological distances.

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Nearby Galaxies and the Galactic Center

Interacting galaxies often produce long streamers of gas, in which “super star clusters” are formed. The GBT will be used to search for diffuse HI connecting the galaxies M83 and NGC 5253 which are suspected of having interacted about 1 Gyr ago. The location and kinematics of this gas are sensitive functions of the details of the interaction between the galaxies. Measurement of the mass and turbulence of the material is critical to understanding the mechanics of super-star-cluster formation as well as the eventual evolution of the two galaxies.

The VLA will continue two large programs that were begun in FY04 to study the structure and motion of the gas in fairly nearby galaxies. The HI gas in the members of a sample of 28 galaxies in the nearby Virgo cluster is being imaged at 15 arcsecond resolution. This program achieves higher velocity resolution, angular resolution, and sensitivity than previous studies. The study of a carefully selected sample of both undisturbed and interacting galaxies will be used to constrain the physical mechanisms driving the evolution of galaxies in more distant clusters. Another sample of nearby galaxies will be imaged in HI at 6 arcsecond resolution in coordination with a multi-wavelength effort supporting the SINGS (SIRTF Nearby Galaxy Survey) program, one of the six “Legacy” projects selected for the Spitzer Space Telescope. Among the goals of this project will be the interplay between the neutral interstellar medium and star formation, as well as the global distribution of both dark and luminous matter in the nearby galaxies.

The relatively nearby (54 Mpc) galaxy SBS 0335-052 is the second most metal-poor galaxy known, having a metallicity about 2.5% of the solar value. As such, it may be a local analog of primordial star formation in the early universe. SBS 0335-052 has been observed previously with the VLA at 22 GHz at 0.3 arcsecond resolution; several 50-pc-sized condensations of emission are apparent, as shown in Figure 2.4. However, resolution near 10 pc is required in order to distinguish individual super star clusters, and accurately model their star formation and the thermal radio emission. The VLA and the Pie Town link will be used at the highest resolution to image continuum emission from this extragalactic starburst, determine the densities, pressures, and stellar masses within the super star clusters, and compare these to higher-metallicity systems in the nearby Universe.

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Figure 2.4. VLA 22 GHz image of the radio emission from the low-metallicity galaxy SBS 0335-052, in contours, overlaid on an I-band (near-infrared) image from HST, shown in colors. The angular resolution of the VLA image will be improved by a factor of five using the A configuration with the Pie Town link, which may resolve individual super star clusters in this galaxy.

Several supernova monitoring programs are expected to continue on the VLA throughout the year. There will be a program to respond to new supernova outbursts and another to monitor the radio emission from outbursts that have been detected over the last 20 years. An increasing number of programs are monitoring nearby starburst and ultraluminous infrared galaxies for new radio supernovae. One of the first of these programs, begun several years ago, discovered a supernova (RSN_NGC 7469) in the Seyfert galaxy NGC 7469, as shown in Figure 2.5. Such supernovae could be of particular interest because the most intense star formation occurs in regions that are optically opaque, so supernova rates derived from optical discoveries may be underestimated. More systematic radio monitoring programs may begin to address this possibility. Supernova rates constrain recent star formation rates in starburst galaxies.

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Figure 2.5. VLA image of the radio supernova discovered in the Seyfert galaxy NGC 7469 in 2000 (Colina et al. 2001). This is one of the first such supernovae detected in extragalactic monitoring programs; several similar programs will be carried out in FY05.

Last year, VLBI imaging of supernova 1986J in the galaxy NGC 891 revealed a new 15 GHz source at its center, located within the supernova shell whose expansion has been measured for years; this source is shown in Figure 2.6. The central source is thought to be either a pulsar wind nebula or the accretion disk of a central black hole. In either case, it indicates the presence of a massive condensed object that was “born” in the supernova. The High Sensitivity Array will be used to determine the radio size of this compact remnant with an accuracy better than 0.2 milliarcseconds, or better than 2000 AU. This, in turn, will enable interesting limits (or measurements) of the expansion speed since the explosion, with an accuracy of a few hundred kilometers per second. Future measurements may provide limits strong enough to distinguish between an expanding pulsar wind nebula and a black hole born in the supernova explosion.

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Figure 2.6. Radio image of young supernova 1986J in NGC 891, at a distance of 9 Mpc. The red image and the contours show the expanding supernova shell imaged at 5 GHz, while the blue central peak is the newly discovered compact source at its center. The size and expansion speed of this central source will be measured using the High Sensitivity Array of VLBI antennas in FY05.

Late in 2004 a challenging experiment using about 50 hours of exactly simultaneous observations with the VLA and the Chandra X-ray Observatory will be carried out. M31*, the faint nuclear radio source in the center of Andromeda, will be imaged at 6 cm with the VLA in A or B Confriguration, simultaneous with Chandra. The goal is to detect variable radio and X-ray emission and to accurately place the radio source in the rich field of X-ray sources, yielding the first reliable radio/X-ray association and providing confirmation of its association with an AGN.

An interesting low-frequency VLA program will observe Sgr A* itself, at resolution of roughly 10,000 Astronomical Units (AU), in order to help model the structure of the radio source near the 4-million- solar-mass black hole at the center of the Milky Way. Figure 2.7 shows the apparent size of the radio source as measured at a variety of frequencies by the VLBA. This measured size has been deconvolved from both the VLBA beam size and the modeled scattering size of the interstellar medium along the propagation direction. At present, the dominant source of error in the VLBI determination of the size and structure of this radio source is the uncertainty in the properties of the radio-wave scattering medium along the line of sight to Sgr A*. VLA imaging of the Galactic Center will take place in FY05 at four

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different radio frequencies between 1.3 and 1.6 GHz. This will enable the model of the scattering medium to be improved and should result in a higher-confidence measurement of the smallest emission structure that can be seen around the central black hole.

Figure 2.7. Plot of the radio size of Sgr A* measured by the VLBA, as a function of wavelength. The size reduction at shorter wavelengths is the residual after subtraction of a model of the size induced by scattering of radio waves within the interstellar medium in our Galaxy, and apparently is a true measure of the size of the central radio source. The diameter of the radio source at 0.7 cm (43 GHz) is only about 12 times the diameter of the event horizon of the black hole at the center of the Milky Way. RS is the Schwarzschild radius.

Molecular Clouds, Star Formation, and Galactic Structure

Some molecular clouds are observed to contain dense condensations that, if they are self-gravitating, might be the progenitors of stars and star clusters. The GBT will be used to measure spectra in the ammonia lines toward a sample of dense cores identified from sub-mm observations of the W3 molecular cloud. The ammonia line widths will give a measure of the turbulence in a core while the line strengths will give the density, which can be used to derive the mass of each core and determine whether it is gravitationally bound or an unbound clump.

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Additional information about the process of star formation can be obtained by imaging the ammonia emission. For example, two hot cores that are expected to evolve into massive protostars will be imaged with the VLA using observations of the 43 GHz NH3 (4,4) emission. Previous observations have shown that these cores remain compact on sub-arcsecond scales, but resolution of 0.1 arcseconds (500 AU) is required to identify the star-formation sites within the hot cores. The use of the spectral line enables not just the structures to be imaged, but also the velocity fields within the hot core regions to be measured. These small-scale velocity measurements could have a significant impact on a current controversy regarding high-mass stars, namely whether or not it is possible to form such stars by accretion in spite of the apparent limitations imposed by radiation pressure, which would tend to blow the accretion disks apart.

It is clear that the interstellar magnetic field has a critical role in star formation, but it can often be difficult to measure. The molecule CCS is found in cores of molecular clouds where the density exceeds 104 cm-3. It is a very useful molecule for measuring Zeeman splitting and thus the magnetic field strength in cloud cores. The GBT will be used to measure the 11.1 GHz line of CCS in a selection of sources to define the role of the magnetic field in the process of core collapse and star formation.

Young protostars can also be explored by the study of their continuum radio emission. Such objects typically have circumstellar disks that are likely protoplanetary disks; i.e., these disks may eventually form planets orbiting the new stars. Recent results indicate that the youngest protostars (Class 0) may have smaller disks than the somewhat older (Class I) objects. If true, this would indicate that the protoplanetary disk radii grow in time as the central stars evolve, and this evolution then must be considered in the context of planet formation in the disks. Figure 2.8 shows an example, a recent VLA image of a protoplanetary disk with a size of 8 AU that has been found in a Class 0 object. The VLA will be used to image the brightest Class 0 objects seen in C configuration at the 10 times higher resolution of A configuration, in order to find more isolated protoplanetary disks and measure their sizes.

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Figure 2.8. VLA A-configuration continuum image at 43 GHz of the compact protoplanetary disk associated with IRAS 16293-2422B. The measured size is 8 AU.

Previous low-resolution observations of the debris disk around a young K5 star in the nearest group of main-sequence stars (TW Hydrae at 50 pc distance) have shown that the disk flux is proportional to the square of the frequency from submillimeter wavelengths (300 GHz) all the way to the highest VLA frequency of 43 GHz. This suggests either that the dust emission is optically thick or that the individual “dust” particles are extremely large, perhaps en route to forming planets. The distribution of the 43 GHz emission will be probed with a VLA+Pie Town observation having 2 AU resolution, which will be sensitive to a possible central hole. If such a hole exists on a size scale much smaller than our early Solar System, it would indicate that the spectral shape is caused by large particles, an interesting inference for the future of planet formation around the K5 star. The difference between the two possibilities will be further investigated by a deep 8 GHz observation which will probe for a significant supply of centimeter- sized particles in the disk.

A Q-band (38 - 50 GHz) spectral survey of TMC-1 will be scheduled on the GBT in the winter 2004- 2005. TMC-1 has served as the ultimate test-bed for astrochemistry for the past 25 years. This cold dark cloud, whose physical conditions are relatively well known, is the richest source of complex carbon- bearing molecular species known. The great majority of all chemical modeling has been of TMC-1 and has found that chemical abundances differ markedly among several cores embedded throughout the cloud. Some have slow evolution from early-time abundances to steady-state, with steady-state abundances

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being the larger. These species appear to form via slow neutral-neutral reactions. Others, mainly the carbon-rich species, evolve rapidly with much higher abundances at early-time explained by faster ion- molecule reactions early on when C and C+ are abundant, and declining at steady-state as carbon becomes bound as CO. The C/O ratio is highly important in all cases. While the “cyanopolyyne” core is the most rich, it is hoped that a second position may be observed also, having a different set of gas-phase progenitors. A particularly important question is what prevents the adsorption onto grains of the gas phase, given the low temperature and lack of energy sources in TMC-1. A recent chemical model suggests that the depletion of the cyanopolyynes onto grains is at least a factor of 500. The Q-band survey of TMC-1 will be made over a total bandwidth of 200 MHz at the very high spectral resolution (6.1 kHz, or 0.041 km/s) required for the narrow lines. Two orthogonal polarizations will be observed simultaneously. The beam size of 16.8” at 45 GHz is well matched to the core sizes.

The transition between the interstellar disk and halo of our Galaxy is characterized by large structures probably thrust up from the plane and numerous clouds of uncertain origin. The GBT will be used to measure 21 cm HI spectra toward one particularly interesting HI feature in the inner Galaxy which appears as a coherent “whisker” of gas extending from the plane more than 1.5 kpc into the halo (Figure 2.9). The data will determine the physical properties of this object and seek its connection with stellar activity in the disk.

Figure 2.9. Image of the mid-latitude portion of the HI whisker structure that suggests by its appearance that the gas is highly turbulent. Each “wisp” of gas shown here has a mass of hundreds of solar masses and a size of several tens of parsecs.

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Pulsars and Other Radio Stars

Young pulsars are of interest because their properties may be closely tied to their origin in supernova core-collapse. Some young pulsars are embedded in non-thermal radio wind nebulae, but many of the youngest do not have detectable wind nebulae, possibly because they have high magnetic fields and quickly spin down to long periods. The GBT will be used to search for young pulsars toward a set of shell-type supernova remnants that lack central wind nebulae. Pulsars discovered from this survey would likely have different properties than the better known young objects and will contribute to our understanding of the supernova process.

The measurement of pulsar proper motions has been of great importance in the process of identifying pulsars with their associated supernova remnants. A source of particular interest is “The Duck,” an energetic pulsar that is just outside a radio supernova remnant. VLA proper-motion studies to date have given upper limits that appear inconsistent with motion away from the center of the supernova remnant, even though an associated bow shock does appear to indicate relatively rapid motion across the plane of the sky. The solution to this dilemma may be that the pulsar is much older than its spin-down age, or it may be that the pulsar and supernova remnant are just two unrelated objects superimposed by chance. The new observation should be able to detect a proper motion of less than 10 milliarcseconds/yr, the amount predicted for an older associated pulsar, and thus resolve the discrepancy.

Globular clusters are a rich breeding ground for millisecond pulsars and binary pulsars, and contain about half of each of these systems known. The pulsars can be used to constrain the cluster mass distribution and the properties of ionized gas in the cluster. Because all pulsars in a cluster have a well-known distance, they contribute to studies of the luminosity function and other fundamental properties of pulsars. The GBT will be used to search for pulsars in two globular clusters which are of particular interest because they are dense and massive and located near the Galactic Center. It is expected that each contains tens to hundreds of pulsars, but so far only a handful have been detected because of the large interstellar scattering in their direction. With its high sensitivity and wide bandwidths the GBT will be able to detect pulsars at frequencies for which scattering can be minimized.

Regular timing of pulsars in binary systems can yield information on the orbits and the evolution of the orbits, eventually giving the mass of the system, several tests of relativistic effects, and constraints on the level of low-frequency gravitational radiation in the Galaxy. The GBT will be used to continue a program monitoring a set of pulsars in interesting environments, including one descended from a low-mass X-ray binary and another in a close orbit with a 0.1 solar mass white dwarf.

At the center of our Galaxy lies a massive black hole surrounded by a cluster of at least several dozen massive stars. The existence of such a cluster is a puzzle, but unless it is transient, previous generations of stars should have left behind a population of neutron stars, as many as several thousand, in orbit about the black hole. The GBT will be used to search for these radio pulsars, taking advantage of the telescope’s large usable bandwidth at cm wavelengths. If pulsars are discovered, the precise timing of the pulses would allow measurement of several relativistic effects over their orbits and might even characterize properties of the black hole itself.

Two groups will take advantage of the Pie Town link to achieve increased resolution in an effort to image the extended atmospheres of nearby red supergiant stars. One program is aimed at multi-frequency imaging of Betelgeuse (" Ori) on the finest scales, over two consecutive A configurations. The evolution

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of the wind structure in the extended atmosphere of Betelgeuse will be studied as newly discovered asymmetries evolve. The other program will observe Antares (" Sco) and Rasalgethi (" Her) at both 22 and 43 GHz in order to measure their radio sizes and see whether their structures reveal asymmetric winds similar to those seen in Betelgeuse. Similar observations were attempted four years ago, but results were uncertain due to poor weather. The completion of all 43 GHz receivers and reduction of noise on the 22 GHz systems will permit more rapid calibration and self-calibration, reducing susceptibility to atmospheric coherence losses.

In late September 2004 the Chandra X-ray Observatory and the Very Large Array will perform coordinated observations of the active binary system CC Eridani in a campaign at X-ray, optical, and radio wavelengths. The objective of the project is to study the relationship between magnetic field structure (observed in the photosphere and extrapolated into the corona), thermal coronal emission (given by X-ray observations), and the nonthermal electron distribution (deduced from radio observations). Other telescopes involved in the campaign will be the ATCA and AAT, and smaller optical telescopes. High spectral resolution X-ray grating observations constrain coronal structures; multi-frequency radio coverage describes the population of nonthermal electrons, and Zeeman Doppler Imaging observations constrain the shape of the photospheric magnetic field, which can then be extrapolated (via potential field calculations) into the corona. The X-ray and radio emission both depend on the structure of the coronal field, albeit in different ways, due to the differing thermal (X-ray) and nonthermal (radio) nature. The large-scale thermal coronal structure, as deduced from X-ray observations, and large-scale nonthermal coronal structure, as deduced from multi-frequency radio observations, can be compared with each other and with extrapolations from the photospheric magnetic-field geometry. Active binary systems are ideal candidates for such a study, due to their large starspots, evidence for large magnetic filling factors, and their large X-ray and radio fluxes, which permit a detailed study of the coronal structure and dynamics.

One of the intriguing results found by the VLBA over its last several years has come from the studies of motions of material in the circumstellar envelopes of stars that have evolved beyond the red supergiant stage. The circumstellar material is outlined by the presence of numerous SiO maser spots whose three- dimensional motions can be traced by repeated VLBI observations at 43 GHz. However, one of the unsolved mysteries has been that the VLBA typically detects no more than 50% of the flux density seen in the masers by single telescopes. This flux may be divided up among many very weak individual maser components, or else within a large region that is resolved out by the VLBA. The HSA will be used to image one such object, IRC+10011, with a sensitivity that is a factor of 7 better than with the VLBA alone. The much lower noise levels will permit a detection of weaker and partly resolved masers, thus enabling a distinction to be made between the two interpretations for the missing flux.

The discovery of radio emission from brown dwarfs in the last few years has piqued astronomers’ interests about the atmospheres of these ultracool objects. Two unanswered questions are: (1) the emission mechanism(s) which gives rise to the observed steady and flaring radio emission, and (2) the frequency of brown-dwarf radio emission. Current understanding of brown-dwarf atmospheres suggests that they are highly neutral and unable to sustain large magnetic stresses; thus it is puzzling that such large flux densities (up to 1 mJy) are observed at high frequencies (8 GHz), which would normally require either large ambient densities or large magnetic field strengths. Recently, a deep multi-frequency VLA observation of a previously detected brown dwarf (spectral type M9) revealed flux-density spectra consistent with patterns seen in earlier M dwarfs. In the next year, deep multi-frequency observations of a sample of brown dwarfs over a range of spectral types, having single-frequency detections, will be performed to explore the ubiquity of this trend. The VLA is currently performing a volume-limited survey of radio emission from nearby brown dwarfs (out to 13 pc) to determine the frequency with which

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brown dwarfs exhibit radio emission. Such measurements are crucial to connect radio behavior with trends of chromospheric and coronal activity in ultracool objects. In the next year, reduction and analysis of the data will be performed, and correlations with chromospheric activity and other stellar properties will be examined. Archival analysis of a large volume-limited survey of M dwarfs carried out from 1986- 1992 will be done to make statistical comparisons with the newly obtained results from L and T dwarfs. The connection between coronal activity as measured by radio fluxes and coronal activity diagnosed by X-ray emission will also be investigated. Chandra and the VLA will observe a nearby L dwarf, Kelu-1, allowing for an investigation of the X-ray and radio properties of this star.

Solar System; Geophysics

The rotation of a planet is modulated by the physical condition of its interior: by determining the amplitude of rotational librations one can distinguish between a solid and a liquid core, for example. In FY05 the GBT, in conjunction with the Goldstone antenna, will be used to measure the pattern of backscattered radar from Mercury and Venus. The rotation of these planets makes their backscattered radar “speckles” move across the earth. By cross-correlating speckle arrival times between Goldstone and the GBT, the planet’s rotation can be measured with extremely high accuracy. These data will measure the extent of the core-mantle coupling and may also detect seasonal rotational changes on Venus due to its atmospheric dynamics.

The VLA will be used to image the leading and trailing hemispheres of Saturn’s largest moon, Titan, at 22 and 43 GHz. Brightness-temperature variations over the surface may constrain the locations of liquids and ices, revealing the possible location of liquids at the landing site for Cassini’s Huygens probe, which is scheduled to descend to the surface of Titan in mid-January. In addition, the VLBA and GBT will be used together in an astrometric VLBI experiment to track directly the probe’s signal as it descends toward Titan. This will enable three-dimensional measurements of the probe motion (Doppler measurements from the Cassini spacecraft and the GBT in addition to VLBI), providing new results for one of the key scientific elements of a $3.3 billion NASA/ESA mission.

Multi-configuration imaging of Uranus will be used to track the seasonal changes in the planetary atmosphere. The use of multiple frequencies will allow probes to different pressure levels, providing new information on the depths of the different weather layers in the giant planet atmosphere.

Radio observations of the Sun provide important insights into a wide variety of physical processes in the solar atmosphere, including the structure and dynamics of the solar chromosphere and corona, coronal magnetic fields, and transient energetic phenomena such as flares, radio bursts, and coronal mass ejections. Radio observations also play an important role in probing the outer corona and the inner heliosphere. A number of radio diagnostics that exploit propagation phenomena—e.g., angular broadening and interplanetary scintillations—have been utilized to constrain the nature of the turbulent solar wind. VLA observations have played a prominent role in all of these areas in past years and will continue to do so in FY2005. It is expected that as the Sun declines from maximum to minimum activity levels, the research focus will turn from energetic phenomena to the quiet Sun.

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The Global Positioning System (GPS) is now being designed into the next generation of aircraft landing systems, and researchers continue to find means to exploit this satellite system in novel ways. There are slight variations, however, in the signals coming from different satellites, and to understand this potential error source it is necessary to quantify the signal distortions from the satellites. The GBT will be used to monitor all 27 GPS satellites now in orbit to characterize their individual signals with the highest signal- to-noise ratio.

The ionosphere of the Earth contains significant structure in its electron distribution on scales both small and large. The GBT will be used to study the electron structures by observing a series of satellites as they are illuminated by ground-based radar. From these data it will be possible to estimate the extent to which ionospheric irregularities will compromise low-frequency aperture synthesis, among other applications.

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3. ALMA Construction

Project Overview

The Atacama Large Millimeter/Submillimeter Array (ALMA) is an array of 64 telescopes that will provide an unprecedented combination of sensitivity, angular resolution, and imaging fidelity at the shortest radio wavelengths for which the Earth’s atmosphere is not opaque. It will image stars and planets being formed from gas clouds near the Sun, and it will observe the first galaxies forming at the edge of the observable universe, which we see now as they were more than ten billion years ago. To minimize disruptive absorption and emission by the Earth’s atmosphere, the array will be located in the Llano de Chajnantor at 5,000 m (16,500 feet) elevation and downwind from the world’s driest desert, the Atacama in northern Chile. The ALMA is an international astronomy facility. ALMA is an equal partnership between Europe and North America, in cooperation with the Republic of Chile, and is funded in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC), and in Europe by the European Southern Observatory (ESO) and Spain. ALMA construction and operations are led on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI), and on behalf of Europe by ESO.

Figure 3.1. Artists rendering of ALMA Operations.

The North American participation in ALMA is executed by AUI/NRAO and funded by the NSF through a Cooperative Agreement with AUI. The U.S. participation in ALMA grew out of the Millimeter Array (MMA) Project, which was proposed to the NSF in 1990 by AUI and funded for a three-year Design and Development phase that began in 1998. In 1999, the NSF agreed with the European coalition to merge the MMA with the European Large Southern Array (LSA) project to create the bilateral ALMA Project. Subsequently, the NRAO and ESO ALMA project management teams worked cooperatively on a common design and prototyping effort. This work led to a jointly agreed work breakdown structure (WBS) for the construction phase of the bilateral project. The WBS includes a thorough cost estimate, a project schedule, and specifies the division of effort. A Joint ALMA Office (JAO), led by the ALMA

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Director, provides a unifying management layer that brings together the efforts of the two Executives (AUI/NRAO and ESO). The construction phase in the U.S. began in 2002, and ESO formally began construction in January 2003. A bilateral agreement between North America and Europe was signed in 2003.

Science Objectives

The ALMA Level-1 Science Requirements are:

The ability to provide precise images at an angular resolution comparable with that expected from the James Webb Space Telescope (JWST), finer than 0.1 arcsec. The term “precise imaging” means images not limited by imaging artifacts at a dynamic range less than 1000:1 over the entire sky visible from the ALMA site. The sensitivity to detect CO emission from a normal galaxy like the Milky Way at a redshift z = 3 in less than 24 hours of observation. A scientifically related requirement is the ability to image the kinematics of such a galaxy using the NII or CII emission line in a single source transit. The ability to image the gas kinematics in a solar-mass protostar having a protoplanetary disk lying at the distance of the star-forming clouds in Ophiuchus or Corona Australis.

The ALMA Project will provide scientists with an instrument uniquely capable of producing detailed images showing the formation of galaxies, stars, planets, and the chemical precursors necessary for life itself.

ALMA is designed to operate in the 0.4 to 9 millimeter wavelength region where the Earth’s atmosphere above a high, dry site is partially transparent and where clouds of cold gas as close as the nearest stars or as distant as the bounds of the observable universe have their characteristic spectral signatures. ALMA provides a window on celestial origins spanning all of space and time.

A wealth of new scientific opportunities flow from ALMA’s orders-of-magnitude improvements in sensitivity, angular resolution, and imaging fidelity at the shortest radio wavelengths accessible from the Earth’s surface. ALMA was designed to allow astronomers to:

Image the redshifted dust continuum emission from evolving galaxies since the epoch of formation as early as z = 10. Follow, through spectroscopy of molecues and atoms, the changing chemical composition of star- forming gas in galaxies throughout the history of the universe. Trace the kinematics of dust-obscured galactic nuclei and quasi-stellar objects on spatial scales smaller than 300 light-years. Assess the influence that chemical and isotopic gradients in galactic disks have on the formation of spiral structure. See into gas-rich and heavily obscured regions that are spawning protostars, protoplanets, and pre-planetary disks. Measure photospheric temperatures of thousands of nearby stars in every part of the Hertzsprung- Russell diagram. Reveal the crucial isotopic and chemical gradients within circumstellar shells that reflect the history of nuclear processing deep in stellar cores.

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Obtain unobscured sub-arcsecond images of cometary nuclei, hundreds of asteroids, Centaurs, and Kuiper-belt objects in the solar system along with images of the planets and their satellites— observations that can be done for astrometric or astronomical purposes during both day and night. Image solar active regions and investigate the physics of particle acceleration on the surface of the Sun.

This list of specific science goals leads to a definition of common science requirements that imply technical specifications for ALMA performance. Foremost among those science requirements are precision high-resolution imaging and high sensitivity. Together they enable the entire spectrum of science to be done with ALMA, irrespective of whether the scientist wishes to study solar-system objects or galaxies twelve billion light-years away.

Technical Objectives

The technical challenge to the ALMA designers is to build a telescope that extends the high-resolution imaging techniques of radio astronomy to millimeter and submillimeter wavelengths.

High-Resolution Imaging

High-resolution imaging at radio wavelengths uses the technique of aperture synthesis, in which an array of many small antennas working together achieves the resolution of a single enormous antenna whose size equals the area spanned by the array. Aperture synthesis is used, for instance, by the Very Large Array of 27 25-m dish antennas to make high-resolution images at centimeter and meter wavelengths. ALMA will use 64 precision 12-m antennas operating in concert at millimeter and submillimeter wavelengths. Signals received by sensitive superconducting receivers on each antenna will be digitized and processed in a special-purpose computer or signal correlator. The image-forming optics of ALMA is also a computer. Images of astronomical objects and cosmic phenomena will be made using computer algorithms designed to correct for atmospheric distortions and combine data from the individual antenna elements.

Many astronomical objects are embedded in larger structures that are physically or causally related. Examples include a protoplanetary disk forming within the molecular envelope of a protostar and the active nucleus at the center of a spiral galaxy. In many cases, the environment of an astronomical object illuminates its origin or evolution. Consequently, scientists need to image both very small structures (the protoplanetary disk or galactic nucleus) with high angular resolution and much larger embedding structures (the molecular cloud or spiral galaxy) with lower angular resolution and a wider field-of-view. ALMA realizes this zoom-lens capability by means of rearranging the physical layout of the antennas on the site to increase or decrease the area spanned by the array.

The antennas can be moved between large and small configurations by a special forklift-type vehicle, but they must be mounted on fixed concrete foundations while observing. ALMA has 217 antenna foundations or “stations” for its five array configurations. Each station is permanently connected to the site electrical power and communication network. An antenna moved from one station to another can simply be reconnected and it will be ready to resume observations. The largest array configuration is a Y-shape nearly 14 km across. It will yield images with angular resolutions as fine as 0.007 arcsec.

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Sensitivity

In order to detect the faintest astronomical sources, ALMA must be significantly more sensitive than existing millimeter and submillimeter arrays. This sensitivity is obtained from the large collecting area of 64 high-efficiency 12-m antennas, low levels of receiver and atmospheric noise, and a wide-bandwidth correlator. The ALMA synthetic aperture must remain coherent; this sets a specification on the permissible instrumental phase distortion, which in turn sets a specification for many things including the accuracy of the antenna primary mirror surface, the stiffness of the antenna backup structure and quadripod support, and the phase noise resulting from transmission of the local-oscillator reference signal in fiber optic cables. The ALMA receiver noise specifications approach the theoretical quantum noise limit.

Operation at Millimeter and Submillimeter Wavelengths

The challenge of engineering the unique ALMA telescope to operate at millimeter and submillimeter wavelengths begins with the telescope site. Water vapor in the Earth’s atmosphere absorbs radio radiation from astronomical sources at millimeter and submillimeter wavelengths so heavily that very little reaches the ground at most locations. The solution is to observe through the thin, dry air found only above deserts at high elevations. ALMA will be located in the Altiplano of northern Chile at an elevation of 5,000 meters (16,500 feet) above sea level. This area, the Llano de Chajnantor, is directly east (downwind) from the Atacama desert, the driest in the world. The ALMA site is the highest permanent astronomical-observing site in the world. ALMA has the difficult task of continuously operating 64 precisely tuned antennas, each weighing more than 100 tons, superconducting electronics cryogenically cooled to less than four degrees above absolute zero, and optical transmission lines carrying terabit data rates, all on a remote site over three miles high in the Andes mountains.

ALMA Project Scope and Specification

All of these requirements serve to define the ALMA technical system, or project scope and specification, as outlined for the bilateral ALMA project in Table 3.1.

Table 3.1 Baseline Bilateral ALMA Scope and Specification Array Number of Antennas 64 Total Collecting Area (ND2) 7238 m2 Total Collecting Length (ND) 768 m Angular Resolution 0.2" λ (mm)/Baseline (km) Array Configurations {Dimension of filled area} Compact: Filled 150 m Continuous Zoom 200-5000 m Highest Resolution 14.0 km Total Number of Antenna Stations 217 Antennas Diameter 12 m Surface Accuracy 25 µm RMS Pointing 0.6" RSS in 9 m/s wind

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Table 3.1 (cont’d) Baseline Bilateral ALMA Scope and Specification Path Length Error <15 µm (sidereal tracking) Fast Switch 1.5˚ in 1.5 seconds Total Power Instrumented and gain stabilized Transportable By vehicle with rubber tires Receivers 84-119 GHz SIS {All frequency bands} 211-275 GHz SIS Dual polarization 275-370 GHz SIS Noise performance limited by atmosphere 602-720 GHz SIS Water Vapor Radiometer 183 GHz Intermediate Frequency (IF) Bandwidth 8 GHz, each polarization IF Transmission Digital Fiber Optic Correlator Correlated baselines 2016 Bandwidth 16 GHz per antenna Spectral Channels 4096 per IF Data Rate Data Transmission from Antennas 120 GB/s per antenna, continuous Signal Processing at the Correlator 1.6 x 1016 multiply/add per second

Project Status

The construction phase in the U.S. began in 2002, and ESO formally began construction in January 2003. The current status of each of the Level-1 WBS elements is described below.

Administration

The principal administrative task is to establish a thorough management structure for the joint U.S.- European project and to implement that structure within the technical teams. The approach adopted is based on Integrated Product Teams (IPTs) in which the work is executed jointly by the technical teams of both partners. That is, responsibility for specific tasks is assigned but the overall effort is shared.

Joint ALMA Office

The Joint ALMA Office (JAO) was created by the ALMA Board as the central management structure for the ALMA construction phase. The JAO will ultimately have an ALMA Director, Project Manager, Project Scientist, and Project Engineer. The three key JAO positions currently filled are:

Massimo Tarenghi ALMA Director Anthony Beasley ALMA Project Manager Rick Murowinski ALMA Project Engineer

An international search is underway to fill the Project Scientist position.

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The two Executives (AUI/NRAO and ESO) have initiated a Project Management Control System (PMCS) for the ALMA project as a whole. The PMCS program includes both the development of the necessary tools and procedures for tracking the project and the development of a project-wide Integrated Project Schedule (IPS). The first version of the IPS will be complete by the fourth quarter of 2004. It will form the performance baseline for an Earned Value Analysis.

Figure 3.2. Design of the Project Management Control System being implemented across the ALMA Project.

North American Project Office

The North American Project Office is being reorganized and expanded. Dr. Adrian Russell, currently Director of the U.K. Astronomy Technology Centre, has been recruited as the new North American Project Manager. He will officially begin his duties in early January 2005. Marc Rafal, who was previously the Project Manager, has assumed the new position of Deputy Project Manager. Fred K. Y. Lo has assumed the position of Interim Project Manager until Dr. Russell’s arrival.

Dr. Richard Simon, who has previously held the position of Controller for the North American Project Office has assumed the Controller position within the JAO. David Hubbard, the NRAO Program Office Head, has been appointed Interim Controller while a permanent position is recruited. The Controller position will be reorganized under the North American ALMA Business Manager, William Porter. Additional project coordinator positions have been created within the project office to assist the North American IPT leads collect, analyze, and report status information using the PMCS system.

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Site Development

Detailed design for the civil infrastructure on the Chajnantor site is underway. In addition to the foundations required for the 217 antenna stations, a technical building, the Correlator, and centrally located portions of the Back End and Local Oscillator subsystems will be located on the high-altitude Array Operations Site (AOS).

On November 6, 2003, ground was broken at the site of the future Operations Support Facility (OSF) for ALMA, at an altitude of 9,600 feet. Road access from the public highway to both the OSF and the AOS is now complete. Following completion of the major civil construction activities, these construction roads will be further improved.

Figure 3.3. Road leading to the OSF from public highway.

A temporary camp facility has been established at the lower-altitude OSF to house ALMA and contractor personnel during construction. The camp will ultimately provide board and lodging for more than 200 personnel.

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Figure 3.4. ALMA Camp facilities at the Observatory Support Facility.

Antennas

Evaluation of the two ALMA prototype antennas has been completed at the ALMA Test Facility (ATF) by a joint evaluation team. Performance of the antennas was tested in the areas of pointing, surface accuracy, and path-length error. A summary of the analysis and conclusions was used to assist in the analysis of offers received for production antennas.

Figure 3.5. VertexRSI and AEC Prototype Antennas.

Procurement of the production antennas requires significant cooperation between the Executives and the JAO. A joint procurement plan was developed for parallel procurements by the two Executives. A Request for Proposal (RFP) from AUI/NRAO and Call for Tender (CFT) from ESO were simultaneously released in December. Both are based on identical Statement of Work and Technical Specification documents. The Business Terms and Conditions were coordinated where possible, but follow each Executive’s procurement rules and procedures.

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Proposals were received in April 2004 and were evaluated on technical and management issues by the Joint Technical Evaluation Team (JTET). In addition, AUI/NRAO conducted a business evaluation with a separate Business Evaluation Committee. The JTET and BEC completed their evaluations and delivered written reports to the AUI/NRAO Contract Selection Committee (CSC). The CSC made a recommendation to the NRAO Director and the AUI President.

The two executives are currently meeting to coordinate the final decisions. Final negotiations and contract award are anticipated in October 2004 following NSF and ALMA Board approval.

Front-end Subsystem

The front end for each ALMA antenna will be contained in a single cryogenic dewar designed to accommodate ten receiver cartridges, one per wavelength band. Initially only four cartridges will be built, for the bands at 3 mm, 1 mm, 0.85 mm, and 0.45 mm. Current plans are for the 3 mm cartridge to be built in Canada and the 1 mm cartridge to be built at the NRAO Technology Center in Charlottesville. The 0.85 mm and 0.45 mm cartridges are the responsibility of the Europeans. Significant progress has been made on the components that make up each of the cartridges.

Figure 3.6. Completed prototype Front End Cryostat.

A prototype 1 mm cartridge has been assembled and successfully tested. Production of the first eight 1 mm cartridges has begun, and the first production unit will be completed early in FY2005. Integration of the band cartridges with the cryostat and support electronics will be carried out at two Front-End Integration Centers, one in the U.S. and one in Europe.

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Figure 3.7. Band 6 (1 mm) Cartridge Assembly.

Back-end and Correlator Subsystems

The 16 GHz analog IF output of each ALMA front end is digitally sampled at the antennas, and the digital signal is sent by fiber optic cables to the correlator. Prototypes of the hardware needed for the sampler and the IF transmission have been delivered to Prototype Integration. They provide functional capabilities to support prototype integration but are not yet identical to production units. Design changes underway for these modules will significantly reduce production cost, accommodate recent updates to system requirements, and resolve design deficiencies.

Correlator

The ALMA Correlator performs digital filtering, delay adjustment, and cross-correlation calculations on the digital signals received at the AOS buildings, at a rate of 96 Gbit/sec for each of the 64 antennas. The net computation rate for the cross-correlation section is 1.7 x 1016 multiply-and-add operations per second.

A prototype correlator capable of handling the entire 16 GHz bandwidth for two antennas was built, tested, and delivered to Socorro for use in system integration. An end-to-end test of the entire digital data generation, transmission, and correlation system was successfully conducted: a sine-wave signal input to a digitizer was formatted, transmitted digitally over optical fiber, received, decoded, and correlated to produce a spectral plot in the data-processing computer.

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Figure 3.8. Production Correlator under construction.

The European effort to plan for a second-generation correlator was merged with the baseline correlator work. This resulted in the incorporation of an advanced 32-output digital filter bank in place of the baseline single-output digital filter, so the frequency resolution available in the widest bandwidth mode will be 32 times finer than before.

A change in the procurement strategy was made: instead of ordering components for the correlator separately for each quadrant at one-year intervals, contracts have been placed for essentially everything for all quadrants (the few exceptions being stock items such as racks). All of the circuit boards, bins, cables, etc. will be produced commercially as turn-key jobs. The net result is a substantial savings in fabrication costs. This has made it possible to adopt the slightly more expensive 32-output tunable filter bank and remain well within the original correlator budget.

A correlator assembly and test laboratory was completed. It has sufficient space and cooling capacity to accommodate and power up two quadrants of the correlator simultaneously.

As of the end of FY2004, almost all of the elements of the first quadrant of the correlator have been manufactured, delivered, and tested. The first quadrant will be able to handle up to 16 antennas with full bandwidth.

Computing Subsystem

The computing subsystem provides the software needed to operate ALMA as well as collect, calibrate, and archive the astronomical data. The software system is being designed in concert with the ALMA software group in Europe. Detailed science software requirements have been developed for all ALMA software elements.

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A successful Computing Critical Design Review (CDR) was held during FY2004. The review panel included software experts from outside the project as well as from the project itself. The panel was chaired by Rodger Doxsey of the Space Telescope Science Institute.

Systems Engineering and Integration

Significant effort has been put towards strengthening the Systems Engineering IPT. Rick Murowinski, as ALMA Project Engineer, is responsible for Systems Engineering. Systems Engineering held a productive Systems Design Review during FY2004. The review identified areas where the top-level systems requirements were inconsistent with draft subsystem requirements. Such discrepancies are being reviewed and resolved via discussions between Systems Engineering, the affected subsystems, and the Science and Management IPT.

Systems Engineering is also leading the Prototype Systems Integration effort. Initial integration is conducted in the lab by integrating both the hardware and software for all prototype modules. Following lab integration, the hardware will be moved to the ALMA Test Facility and installed on the two prototype antennas. This will allow a complete end-to-end test of the ALMA hardware and software prior to beginning integration in Chile.

Finally, detailed planning is underway for the integration task in Chile. Detailed materials flow, logistics planning, and manpower requirements are being reviewed.

Science and Imaging

The Science and Imaging IPT is responsible for designing the array configurations that will maximize the imaging capability of the instrument and establishing the calibration system necessary for precision imaging.

The configuration design has been completed and the station locations have been determined. All of the station locations have been surveyed and staked at the site. A small number of stations may require relocation to avoid poor soil or subterranean rock conditions.

The Science and Imaging IPT has developed a comprehensive Science Reference Plan (SRP). The SRP includes a set of observing sequences designed to be representative of the observations that ALMA is expected to make. The SRP is used to analyze the efficiency of various operational scenarios and to test assumptions about data volume and appropriate sizing of data communication and storage infrastructure.

Program FY2005

As described above, the project is currently implementing an enhanced PMCS that will provide more detailed analysis and tracking of project status. A fully functional PMCS with a complete integrated project schedule will be available during FY2005. In addition, procurement of the production antennas and completion of production plans for the remaining ALMA hardware will provide more accurate estimates of the cost and schedule to completion. As a result, a major effort over FY2005 will be preparation and planning for a potential project rebaselining that accommodates this updated information. Based on a recommendation by the ALMA Management Advisory Committee, it is also anticipated that the ALMA Board will initiate a project-wide review of ALMA management and planning activities.

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The current North American ALMA milestones for FY2005 are shown in Table 3.2 below. The completion of the PMCS system will result in a significant reorganization of the milestones to more uniformly represent the flow of activities from unit production to prototype systems integration and ultimately to systems integration in Chile. While the definition and reporting of milestones will change during this period, the fundamental technical work for FY2005 is expected to continue as planned.

Table 3.2 North American ALMA FY2005 Milestones IPT WBS Level Scheduled Milestone or Deliverable Number Quarter Site 2.025.20704 3 1 Submit Draft weather station plans Site 2.025.8224 2 1 AOS Foundations NA Central Cluster Construction Tender Docs Complete Site 2.025.8226 2 2 AOS Foundations NA Central Cluster Construction Contract Signed Site 2.025.8230 2 2 AOS Foundations NA Remaining Construction / Tender Docs Complete Site 2.025.8232 2 3 AOS Foundations NA Remaining Construction Contract Signed Site 2.025.8252 2 1 AOS Buildings NA Foundations/Envelope Construction / Tender Docs Complete Site 2.025.8254 2 1 AOS Buildings NA Foundations/Envelope Construction Contract Signed Site 2.025.8258 2 3 AOS Buildings NA Foundations/Envelope Provisional Acceptance Site 2.025.8260 2 1 AOS Buildings Finish & Installations NA CDR Complete Site 2.025.8262 2 1 AOS Buildings Finish & Installations NA Construction / Tender Docs Complete Site 2.025.8264 2 1 AOS Buildings Finish & Installations NA Construction Contract Signed Site 2.025.8360 2 1 Freeze Fiber Optics and Electrical Specifications Site 2.025.8362 2 1 Fiber Optic Cables and Electrical Cables in Chile, N.A. Site 2.025.8374 2 2 ALMA Permanent Power Supply Tender Docs Complete Site 2.025.8376 2 3 ALMA Permanent Power Supply Contract Signed Antenna 3.050.8565 2 1 Sign Contract for 31+1 North Am. Production Antennas Antenna 3.065.8555 2 1 Nutator Critical Design Review Completed Front End 4.075.8990 2 2 Front end sub-system Delta PDR passed Front End 4.075.8995 2 1 All FE Contracts / Agreements in place Front End 4.100.8845 2 1 Freeze hardware design M&C circuit Front End 4.100.8860 2 1 Modify ATF M&C software for cartridge manufacturers Front End 4.100.8865 2 1 Deliver FE software req. to computing IPT Front End 4.100.8905 2 1 Freeze the design of the IF switch/processor Front End 4.100.8920 2 1 Freeze the design of the FE chassis Front End 4.100.8922 2 2 Freeze FE Design Front End 4.105.8825 2 1 Deliver DC bias electronics for cartridge #1 Front End 4.105.8830 2 3 Deliver DC bias electronics for cartridge #8 Front End 4.105.8850 2 1 Deliver the monitor and control module for front-end number one Front End 4.105.8855 2 3 Deliver the monitor and control module for front-end number eight Front End 4.105.8910 2 2 Deliver the IF switch/processor for the first front-end Front End 4.105.8915 2 3 Deliver the IF switch/processor for the eighth front-end Front End 4.105.8925 2 1 Deliver the FE chassis for receiver #1 Front End 4.105.8930 2 4 Deliver the FE chassis for receiver #8 Front End 4.145.8935 2 2 Band 3 Cartridge #1 delivered Front End 4.165.8945 2 2 Band 6 Cartridge #1 delivered Front End 4.220.8975 2 1 FE Test & Integration centre design ready Front End 4.230.8980 2 3 NA FE Test & Integration centre operational Front End 4.240.9025 2 4 Issue RFP for FE Service & exchange vehicle Front End 4.258.8890 2 2 Freeze LO design Front End 4.258.8895 2 1 Deliver LO chain(s) for cartridge #1 Front End 4.258.8900 2 2 Deliver LO chain(s) for cartridge #8

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Table 3.2 (cont’d) North American ALMA FY2005 Milestones IPT WBS Level Scheduled Milestone or Deliverable Number Quarter Back End 5.260.50307 3 1 Write Back End ICDs Back End 5.260.50308 3 1 Complete module designs Back End 5.260.50309 3 1 Design and develop test fixtures and automated test sets Back End 5.260.50310 3 2 Complete module and test set construction Back End 5.260.50311 3 2 Complete module testing Back End 5.260.9100 2 1 Deliver BE modules for system integration Back End 5.260.9106 2 1 Deliver Back End Production Plan Back End 5.260.9120 2 2 All BE production contracts placed Back End 5.262.9105 2 2 Install BE hardware on two ALMA prototype antennas at the ATF Back End 5.295.9115 2 1 LO Phase Correction Demonstration Back End 5.295.9117 2 2 End to End LO Demonstration Back End 5.295.9119 2 3 Pre production LO Review Back End 5.305.9122 2 1 Deliver Back End Assemby, Test, & Verification Plan Back End 5.305.9125 2 3 All ALMA assembly, test and verification equipment in place Correlator 6.320.60401 3 1 First motherboard installed Correlator 6.320.60402 3 1 All station PCBs assembled Correlator 6.320.60403 3 2 All motherboards installed Correlator 6.320.60404 3 3 All correlator PCBs assembled Correlator 6.320.60405 3 3 First end-to-end test Correlator 6.320.9240 2 4 Begin integrated testing for first quadrant Correlator 6.320.9255 2 4 Begin Assembly of second quadrant* Correlator 6.320.9260 2 3 Begin board testing for second quadrant Computing 7.340.70322 3 1 Software release to support lab system integration Computing 7.340.70402 3 3 Software release to support first fringes at ATF Computing 7.340.9440 2 3 Subsystem Minor Release 2.1 (R2.1) Computing 7.340.9445 2 3 Subsystem Critical Design Review 3 (CDR3) Computing 7.340.9500 2 1 Subsystem Major Release 2 (R2) Computing 7.340.9520 2 1 Integration Release 2 (IR2) System 8.365.80316 3 1 9602-12 All system level ICD requirements - draft System 8.365.80318 3 1 System Requirement documents submitted for review System 8.365.9602 2 1 System Requirements Review (SRR) - System Requirements Finalized System 8.370.80320 3 2 9659-1 ATF Test Readiness Review (TRR) System 8.370.80321 3 1 9665-1 ATF Post Test Review (PTR) System 8.370.9650 2 1 Prototype Integration & Verification Plan (Q4 '03 thru Q4 '04) approved for Lab & ATF System 8.370.9653 2 1 All hardware for Prototype System Lab Integration accepted and delivered System 8.370.9659 2 2 ALMA prototype electronics and software installed on ATF System 8.370.9662 2 4 First interferometer fringes using prototype antennas at ATF System 8.375.9750 2 1 ALMA Integration & Verification Plan - Q1 2005 through Q4 2007 for OSF and AOS Science 9.380.98353 3 1 Draft WVR software implementation plan Science 9.380.9840 2 2 Review of tests of calibration strategies on prototype interferometer complete Science 9.380.9843 2 3 Review of tests of calibration strategies on ATF interferometer Science 9.380.98431 3 2 Tests of dynamic scheduling on interferometer at ATF. Science 9.380.98452 3 1 Science verification draft for commissioning revised Science 9.380.98701 3 1 Complete draft ICD between Science and Site

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ALMA activities in FY2005 are focused in two major tasks: ALMA Prototype Systems Integration and preparation of the site for the early Production Systems Integration. Figure 3.9 shows a simplified diagram of the ALMA program flow. Starting with the requirements on the left, each IPT produces hardware and software that are delivered first to Prototype Systems Integration and later to Production Systems Integration.

Management IPT

Site IPT

Antenna IPT

Prototype Front-End IPT System Operations Integration Systems Engineering IPT Back-End IPT Science (Requirements) Production Correlator IPT System Integration

Computing IPT

Science IPT Science Verification

Figure 3.9. ALMA Program Flow.

ALMA Prototype Systems Integration is intended to demonstrate the end-to-end capabilities of the ALMA hardware. Prototype Systems Integration initially integrates ALMA hardware and software in the laboratory to establish and verify signal flow from the front end through the back end and correlator. Following laboratory integration, the system will be moved to the ALMA Test Facility (ATF) where it will be integrated with the two prototype antennas to form a single-baseline interferometer. The ATF phase of Prototype Systems Integration will achieve first fringes using ALMA hardware and software. It is intended both to validate the design of the ALMA system and its individual components and to simplify the later Production Systems Integration in Chile.

Preparation of the site in Chile began in FY2004 and will continue in FY2005. Construction of the AOS Technical Building will begin during this fiscal year and will be completed in early 2006. Construction of the OSF Technical Area, an ESO deliverable, is also scheduled to start in 2005. Detailed design of the permanent power plant will also start in 2005. ALMA and contractor personnel will be housed in a temporary camp facility located at the OSF. The camp facility was partially completed in FY2004 and is already occupied. The camp will be enlarged and completed during FY2005.

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3. ALMA Construction

A contract for the production antennas will be executed early in FY2005. The first production antenna will be delivered to the site in FY2006. During FY2005 the contractor will complete design modifications required to accommodate differences in specifications and interfaces of the production and prototype antennas. These modifications will be reviewed during a Pre-Production Design Review (PPDR).

The first pre-production front-end cartridges will be delivered to the Front-End Integration Center during FY2005. These cartridges will be integrated into the first production cryostat at the North American Front-End Integration Center in Charlottesville. Detailed design of the complete front-end chassis started in FY2004 and will be completed in FY2005. Integration of the front end includes installation and connection of the cryostat, front-end cartridges, bias electronics, monitor and control electronics, optical elements, and calibration devices. The completed front end will undergo extensive testing using an automated test set to be completed during FY2005.

Design and fabrication of modules for Prototype Systems Integration was completed in FY2004 with the exception of the digitizer (an ESO deliverable). A prototype digitizer is now scheduled for delivery in December 2005. Development will continue for several back-end modules during FY2005 in parallel with Prototype Systems Integration. These developments will reduce production costs or address design deficiencies of the current prototypes.

Production of the first quadrant of the correlator began in FY2004 and will continue throughout FY2005. During FY2005 the majority of the commercially produced boards required for the first quadrant will be received and tested using already completed test jigs. Assembly of the Correlator racks will be completed and population of the racks with boards will begin. In parallel with completion of the first quadrant, assembly of the second quadrant will be started.

During FY2005 the computing IPT will support Prototype Systems Integration while continuing to deliver software builds that meet an increasing proportion of ALMA requirements. Formal review of the progress towards fulfilling all Early Science requirements is carried out through an annual Incremental Design Review.

The ALMA FY2005 budget and ALMA personnel are included in Section 14 of this NRAO Program Plan.

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4. ALMA Operations

Overview

The ALMA early-science program is to begin in the third quarter of 2007 with an initial array of eight antennas, each with four receiver bands, and the first quadrant of the correlator. This milestone sets the schedule for completion of all systems required for observers to submit proposals for early-science programs; to referee, rank, select, and schedule proposals; to verify array operations and data quality; to archive data and distribute data to observers; and to assist observers with the further analysis of data. The construction of the software for these functions is a task of the ALMA construction team. The testing and evaluation of these software systems is an operations task, one that must begin in 2005 to meet the early- science milestone. These tasks belong to the ALMA Regional Centers (ARCs). The North American ARC is contained within the North American ALMA Science Center (NAASC), located at NRAO, Charlottesville, Virginia. The activities planned for the NAASC, particularly in 2005, are presented below.

ALMA operations consists of more than preparing for early science. Commissioning the array is a major operations task. Antennas will be assembled and equipped with instrumentation at the OSF by the ALMA construction team. Upon certification that it is operational within specifications, the antenna is turned over to ALMA operations for transport to the array site, installation on an antenna pad, and connection to the permanent local-oscillator and intermediate-frequency systems. It is an operations task to establish performance with the correlator and conduct tests of the array as an interferometer. As the array becomes operational, early science programs can be conducted, interspersed with testing and debugging. Antennas will be added to the array in sets of eight, as each set is commissioned. This major task belongs to ALMA operations in Chile, which has the responsibility for directing all ALMA operations including coordination with the ARCs in North America and Europe.

North American ALMA Science Center

The NAASC is the access portal to ALMA for the North American scientific community. In the context of the NRAO, its closest parallel is a telescope operating site like Green Bank or Socorro. The user support facilities of the NASA space telescopes (Hubble, Spitzer, Chandra) are better analogies. The NAASC will be the point of contact for North American ALMA users from proposal submission to calibrated-data distribution and analysis. The heart of this end-to-end data system will be a data archive. Much of the Center’s activity will be the development and maintenance of the pipeline reduction, archiving of data, and software systems that surround it. The NAASC will conduct a program of ALMA Fellows and provide support for data analysis by users. It will be the focus for ALMA affairs in North America, sponsoring workshops, schools, and events that foster community development and guide the future evolution of ALMA. ALMA development projects, both hardware and software, will be conducted by the NAASC. The NAASC will be responsible for ALMA within the NRAO program of education and public outreach.

The following organization chart shows the structure of the NAASC and its relationships within NRAO and to other entities involved in ALMA. It is consistent with the ALMA Project Plan (version of February, 2003) and with the draft ALMA Operations Plan (version I1). A revised ALMA Project Plan is under consideration by the ALMA Board and the ALMA Operations Plan has not yet been submitted to the ALMA Board for approval. Pending ALMA Board action on these two documents, the NAASC Plan described here is subject to further refinement.

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North American Partner North American Partner United States Canada NSF NRC

North American Executive AUI/NRAO AUI/NRAO NAASC Steering Chilean Affairs Committee Office NRAO Director

NAASC ALMA North American Science Advisory Joint ALMA Office Head Committee

Science Technical Services Business Office Data Management

Proposal System Functions Hardware Administration Repair & Maint.

ALMA Fellows Instrumentation Software Students Development Maintenance

Community Archive Support Operations The North American ALMA Regional Center (NAARC) is contained within the NAASC. The NAARC (core) functions are shown in red.

Education & Software Public Outreach Development

Figure 4.1. Organization chart of the NAASC.

The NAASC is organized into four units: Science, Technical Services, Business, and Data Management. One of these, Technical Services, is a sub-activity of the NRAO Technology Center (NTC), supervised by the head of the NTC. The other units will be located in the expanded NRAO Edgemont Road building, shown in the following figure.

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4. ALMA Operations

Figure 4.2. Expanded Edgemont Road Building.

The ALMA Project Plan refers to ALMA Regional Centers (ARCs), and the North American ARC is contained within the NAASC. The ARCs are responsible for so-called core functions; these are given in red in the organization chart. The core functions provide activities necessary to receive and process observing proposals from and make observational data accessible to the user community. The other functions of the NAASC provide required infrastructure, enable and support the derivation of scientific results from ALMA data, foster the development of the user community, conduct a program of ALMA Fellows, and establish a program of ALMA education and public outreach for the United States.

It should be noted that the NAASC is to serve the North American general astronomical community. Canada will share in the support of and benefit from the NAASC proportionate to their share (7%) of the construction of ALMA compared with the United States. The only exceptions to this are data-analysis grants to users and education and public-outreach programs, where Canada will conduct its own programs. A major portion of the Canadian contribution to the NAASC is expected to be in-kind, for example, repair of the electronics built in Canada, work on the archive, and development projects.

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4. ALMA Operations

The NRAO Director receives scientific advice regarding the ALMA Project from the ALMA North American Scientific Advisory Committee (ANASAC). The ANASAC is composed of 17 members drawn from the North American astronomical community and appointed by the Director for staggered terms of two years. Nominations to the ALMA Scientific Advisory Committee (ASAC) from North America are drawn from the ANASAC membership. This structure is parallel to the ALMA science advisory structure in Europe. The ANASAC meets bimonthly to hear reports on the status of the Project, discuss the status of tasks that have been requested of ANASAC by NRAO, and address new issues that may have been sent to the ANASAC. These meetings are attended by the North American ALMA Project Scientist, the Head of the NAASC, and other NRAO/NRC staff as appropriate.

Description of NAASC Functions

The largest unit of the NAASC will be Data Management. The dominant role of data management in the NAASC is similar to the role that computing plays in the science support centers of the NASA astronomy missions, the Very Large Telescope, and user support groups of the other telescopes of the NRAO (whose future evolution is to be patterned on the NAASC). The success of ALMA depends critically on its software systems, and the NAASC is responsible for supporting the software that interfaces most directly with ALMA users, namely, producing software to submit and review proposals, constructing observing programs, receiving and distributing pipeline-produced reference images, operating a data archive, analyzing images, and organizing communications with users via email and internet. (The size of the data-management task is indicated by the following: since its inception, the Hubble Space Telescope archive has grown to 17.6 Tbytes, whereas ALMA is expected to produce 100 Tbytes every year at current, perhaps low, estimates.)

The next-largest unit will be Science. The Deputy Head of the NAASC will lead the Science unit. Five scientists (part of the NA ARC) make up the staff to handle proposal functions, principally helping users in using the Observing Tool to prepare and submit proposals, managing the refereeing and ranking of proposals, and ensuring that accepted proposals are properly characterized for pipeline processing of observational data. The science support activity includes an NAASC Project Scientist, the ALMA Fellows program, a pre-doctoral student program, and a librarian. The ALMA Fellows Program is similar to the Jansky Fellows Program for the rest of the NRAO and the Hubble Fellows Program of the Space Telescope Science Institute, with Fellows able to choose an institution of residence that is not necessarily at NRAO. The community support program, which distributes support to U.S. users for data analysis, requires a secretary/administrative aide. The ALMA education and public outreach includes personnel in both the areas of public information and public science education. It is assumed that the core staff will be supplemented by staff supported on science education grants.

Technical Services is a sub-division of the NRAO Technology Center, headed by the head of the NTC. One team is responsible for the repair and maintenance of NRAO and NRC supplied electronics. A second team will be responsible for the development of new hardware that will be funded by ALMA development funds in the ALMA Operations budget.

The Business Office of the NAASC consists of a business manager and an administrative aide, who will be devoted to NAASC business affairs. Their positions are matrixed with the NRAO Administrative Services Division, as are all other required administrative services (Human Resources, Fiscal, etc.).

The AUI/NRAO Office of Chilean Affairs is not, strictly speaking, part of the NAASC. Rather, it is a set of corporate/observatory functions essential to the operation of ALMA in Chile that include

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4. ALMA Operations

representation of AUI/NRAO to the government of Chile for ALMA, responsibility for ensuring that North America’s share of the business activities of ALMA in Chile are conducted according to the terms of the cooperative agreement between AUI and the NSF and any other regulations that may apply, and any other activity that requires the fiduciary presence of AUI in Chile for ALMA.

User Data-Analysis Grants

The requirements of a program to make funds available to U.S. ALMA users for data analysis, analogous to the NASA program for HST, Spitzer, and Chandra, are not yet fully determined. The ANASAC will conduct a study of community requirements to advise NRAO in defining the necessary scope and guidelines for the program. We do know that such programs are critically important to NASA missions and were strongly endorsed by the last Decadal Report for Astronomy and Astrophysics for new NSF funded facilities. We regard this program as essential to the success of ALMA in the U.S., noting that such support to European users is automatic by virtue of their funding mechanisms.

NAASC Activities in 2005

The NAASC tasks to be accomplished in 2005 are largely organizational and planning in nature, but also include tasks such as software testing, community relations, and preparation of observing tools. There will be two full-time positions supported by ALMA operations funds, the NAASC Head and an Assistant Scientist, and several additional scientists supported by NRAO operations with functional duties in the NAASC.

The following list is a summary of the principal tasks for FY2005.

Completion of detailed plans for the NAASC that are consistent with an ALMA Operations Plan approved by the ALMA Board. The rough outlines of these plans are available today but require work to clearly define the interfaces between Chile operations and the ARCs, determine total requirements year-by-year to full operations, and establish the transition from construction to operations.

Completion of the requirements for a program of support for data analysis by U.S. ALMA observers. The preparatory work has begun with a survey of the community, but FY2005 will have begun by the time the results of the survey have been compiled into a set of requirements.

Testing of the proposal submission tool and organization of the proposal refereeing and ranking system. This is the main activity in a set of tasks that lead up to the first call for early science proposals. Other activities in this area include informing the community of the schedule of resources and array performance that is expected during the interim period from early science until full operation. This will be done in a series of town meetings and workshops. The NAASC web site will be developed as a communications tool for these purposes as well as the place to submit proposals.

Construction will begin on a spectral-line frequency table for a large number of known and possible interstellar molecular species to aid observers in planning and interpreting their observations. The goal is to build the frequency table into the observing/proposal tool and to have it available on-line for widespread and easy access by users.

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4. ALMA Operations

ALMA Operations in Chile

The activities planned for ALMA operations in Chile in FY2005 are also largely organizational and planning in nature. The prime deliverable is the ALMA Operations Plan with a work breakdown structure and budget year-by-year until 2012. Recruitment and training of operations staff must be planned to have sufficient staff in place to receive antennas as they are turned over to operations. Notable among staff requiring training are the transporter drivers, but a complete staffing recruitment and training plan is needed, based on the ALMA Operations Plan.

Another urgent task for ALMA operations in Chile is the development of a plan to acquire spare parts and equipment for critical items, those whose failure significantly impacts operation of the Array until replaced. The construction plan includes no funds for such spares.

Other tasks and a more complete program of activities for FY2005 will be developed by the Joint ALMA Office.

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5. Expanded Very Large Array

Overview

The VLA Expansion Project’s principal technical requirement is to improve the array’s observational capabilities by an order of magnitude or more. This will be done by: (i) adding new frequency bands, (ii) upgrading or replacing current receivers, (iii) replacing the data transmission system and correlator, and, (iv) connecting two VLBA antennas into the array and incorporating new antennas at locations between the VLA and the VLBA. In addition to these, new and more powerful on-line computing will enable better access to the array’s data products, and will give a much improved interface with users.

The effect of these planned improvements and enhancements on the array’s capabilities are comprehensive.

The continuum sensitivity will increase by an order of magnitude or more in several bands. Continuous frequency coverage from 1 to 50 GHz will be obtained. The bandwidth that is transmitted from the antennas, and processed by the correlator, will increase by a factor of 80, from 200 MHz to 16 GHz. The maximum number of spectral channels available, and the maximum frequency resolution, will increase by a factor of over 500. The resolving power will increase tenfold. The new instrument, when cross-linked with the VLBA and with new antennas located about 50- 300 km from the VLA, will greatly enhance the VLBA’s dynamic range, field of view, and frequency scalability.

The impact on astrophysics of making these improvements to the VLA will be profound. Many severe limitations now constraining VLA observations will be removed or greatly relaxed.

A short selection of unique experiments made possible includes:

Measuring the three-dimensional structure of the magnetic field of the Sun. Using the scattering of radio waves to map the changing structure of the dynamic heliosphere. Measuring the rotation speeds of asteroids. Observing ambipolar diffusion and thermal jet motions in young stellar objects. Measuring three-dimensional motions of ionized gas and stars in the center of the Galaxy. Mapping out the magnetic fields in individual galaxy clusters. Conducting unbiased searches for redshifted atomic and molecular absorption lines. Looking through the enshrouding dust to image the formation of high-redshift galaxies. Disentangling starburst from black hole activity in the early universe. Providing direct size and expansion estimates for up to 100 gamma-ray bursts every year. Measuring the parallaxes of pulsars as far away as the Galactic Center. Imaging thermal objects such as stars and novae with milliarcsec resolution.

The expanded VLA will open a vast area of “discovery space,” which is currently inaccessible to any instrument. We can expect that, as with the original VLA, it is likely that the most important discoveries to be made will be those that cannot now be foreseen.

The VLA Expansion Project comprises two major components; Phase I, an upgrade of the existing VLA; and Phase II, the New Mexico array and other enhancements.

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5. Expanded Very Large Array

Phase I

The major components of the first phase of the EVLA Project include the following.

A new correlator, able to support 32 antennas, to process broadband signals and to provide vastly improved resolution and flexibility for spectral-line work. A fiber-optic data transmission system to transmit the broadband signals and monitor data from the antennas to the control building, replacing the original waveguide. New on-line computers, operating software, archiving, and end-to-end data management software, to enable more powerful and flexible interaction between the telescope and the operators and observers. Improved receivers with lower noise temperatures and much wider bandwidth performance (up to 8 GHz in each polarization channel) in existing bands; addition of 2.4 GHz and 33 GHz bands at the Cassegrain focus. The goal is to provide continuous frequency coverage from 1 GHz to 50 GHz in eight frequency bands from the Cassegrain focus.

In May 2000, the NRAO submitted to the NSF a proposal to fund Phase I of the VLA Expansion Project. The proposed plan was for a project which would last nine years, at a total cost of $76M ($ FY 2000). Of this, $50M would be new funding from the NSF, and the remainder would come from expected operations funds redirected to support the project, and foreign partner contributions. After review, the EVLA Management Plan was submitted to the NSF in September 2001, and the National Science Board (NSB) approved the project for construction on November 14, 2001. The funding profile approved by the NSB spanned 11 years.

In FY2004 $4M in accelerated funding was provided in addition to the NSF-approved Mission Requirement Level budget. These augmented funds allow the VLA antennas to be retrofitted to the EVLA design five months earlier than the original baseline plan. As well as accelerating the schedule, these funds are being used to place large production orders of critical electronic and mechanical components to reduce cost by economies of scale and to prevent future problems of component obsolescence.

Good progress was made on the EVLA in FY2004. The major activity for the project was the outfitting of the EVLA Test Antenna (VLA Antenna 13) with prototypes of the EVLA electronics and software systems and the testing of these new systems. First light was obtained on the Test Antenna using a VLA X-band receiver in October, 2003 and first interferometric fringes between the Test Antenna and the VLA antennas were obtained at X-band in March 2004. First fringes at L-band were obtained in June 2004.

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5. Expanded Very Large Array

Figure 5.1. EVLA Test Antenna with the new feed support structure installed.

A major milestone for the project was the completion in February 2004 of installation of the fiber optic cable along the arms of the VLA. This work was completed several months ahead of schedule and under budget, primarily because winter weather and rocky terrain had less impact on progress than had been planned. The work of splicing together the various cables and terminating the fibers in junction boxes at each of the antenna pads still remains.

Figure 5.2. Fiber optic cable installation nearing completion at the end of the East arm of the VLA.

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5. Expanded Very Large Array

Existing VLA receivers for X, L, K, and Q-bands were modified and installed on the test antenna. Construction of new, wide-bandwidth EVLA receivers for L and C-band commenced. The key wide bandwidth components for these receivers are the feeds, orthomode transducers, and amplifiers. Prototypes of these devices were constructed and tested in the laboratory. Prototypes of all Local Oscillator, Intermediate Frequency, Monitor and Control and Digital Transmission electronics modules have been tested. Large quantity production has commenced for those modules that meet all requirements. Many of the modules have required a redesigned second-generation version either to improve performance or reduce production cost. These second-generation versions are under construction and will be installed on the second EVLA antenna. Several of the production-version designs utilize integrated surface-mount technology which provides significant cost savings compared to discrete component designs.

Outfitting of the second EVLA antenna (VLA Antenna 14) began in April 2004.

Figure 5.3. Prototype EVLA L-band feed.

The Canadian Partners (Herzburg Institute of Astrophysics) are making good progress on the detailed design of the correlator. A major decision for this part of the project was the decision to design and fabricate the new correlator chip without first simulating its performance using Field Programmable gate Arrays (FPGA), as originally planned. Bypassing the FPGA step will save both cost and schedule. Four bids for the new correlator chip were received in April, 2004 and the Canadian Partners are working with two of the bidders to determine which design is optimum with respect to cost, performance, and power.

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5. Expanded Very Large Array

Figure 5.4. Prototype L-band orthomode junction.

Planned Activities for FY2005

The optimal EVLA program, as represented by the planned activities below, assumes continued funding at the 2004 level. The optimal funding rate, if continued to the end of the project, would allow retrofitting of the VLA antennas to be completed approximately one year earlier than the current plan. Tasks 8 and 9 will be affected if this optimal funding level is not maintained, and the overall cost-to-complete of the project will be increased.

1. Completion of the outfitting of the second EVLA antenna.

Retrofitting of the second EVLA Test Antenna (VLA Antenna 14) began in May 2004. This antenna is being equipped with second-generation versions of the prototype EVLA hardware that was installed on the first Test Antenna. This second-generation hardware will allow the antenna to operate with four IF bands. The purpose of the second Test Antenna is to test preproduction versions of all hardware prior to the beginning of installation of production hardware on the third EVLA antenna. The antenna will initially have L, K, Q, and X-band receivers to observe with and later the new C-band prototype receiver will be added. The antenna is slated for operation in Q1 2005.

2. Retrofit of the Test Antenna to full EVLA production design.

Antenna 13, the first Test Antenna, will have all of its prototype electronic systems replaced with full production versions in late Q1-2005. When this upgrade is complete it will be able to operate with 4 IF bands and will have L, K, Q, and X-band receivers.

3. Outfitting of 3 additional antennas to EVLA design.

In addition to the completion and upgrading of the two Test Antennas mentioned in items (1) and (2) above, three more VLA antennas will be converted to EVLA design. Of these additional antennas, two will also receive new azimuth bearings (funded from VLA operations budget). VLA Antenna 16,

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5. Expanded Very Large Array

along with its new azimuth bearing installation, will be the first production antenna to be outfitted with EVLA designed production hardware. It will go into operation in Q1-2005 with the use of C, L, K, Q, and X-band receivers. The next two antennas to be outfitted with production hardware, one of which will receive a new azimuth bearing, are slated for operation in early and late Q3-2005 respectively.

4. Continued splicing of the fiber optic cables and termination of the fibers at the antenna pads.

Although all of the fiber optic cables for the EVLA have now been buried along the arms of the VLA, significant work remains to splice together all of the fibers in the cables and to terminate the cables in junction boxes at all 72 of the VLA antenna pads. By the end of FY2005 it is planned that 75% of this work will be completed, with the remainder to be finished in FY 2006. The schedule for connecting antenna pads to the fiber will provide the number of pads required to support the planned outfitting rate of EVLA antennas.

5. Begin installation of the new wideband L, C, and Ka-band receivers on the EVLA antennas.

During FY2005 construction of the prototypes of the new L, C, and Ka-band receivers, commenced in FY2004, will be completed and the production of these receivers will begin. Two C-band receiver prototypes are slated for installation on antennas 14 and 16 in Q1-2005. After a period of evaluating the prototype versions, the production of the C-band receiver will commence. The new wideband L and Ka-band receiver prototypes are slated for installation on an EVLA antenna in June 2005. Production of these two receivers will begin at the end of FY2005.

6. Commencement of routine observing with the EVLA antennas in “transition mode”.

Routine scientific observing with EVLA antennas will begin in Q1-2005 using “transition-mode” hardware and software. In this mode the digital signals received from the EVLA antennas via the new fiber optic transmission system will be used to generate an analog signal which will be fed into the existing VLA baseband and correlator systems. This will allow EVLA antennas to be included in all VLA observations. The EVLA antennas will be monitored and controlled (M/C) by the new EVLA M/C system running on the new EVLA control computer. In Q3-2005 the EVLA control computer will also begin controlling the existing VLA correlator, in preparation for phasing out the existing VLA Modcomp M/C computers. Existing VLA software will be modified so that observing scripts can be supplied for EVLA antennas and so that correlated data from EVLA antennas can be calibrated.

7. Continued design and construction of the EVLA correlator.

The Canadian Partner (HIA) will continue the design and construction of the new EVLA correlator. This work is funded by the Canadian Government and is not contingent on NSF funding. The major goal for HIA during FY2005 is the construction of a prototype subset of the correlator which will be tested on the VLA in 2006. Important milestones towards this goal include placing an order for the new correlator chip in Q4-2004 and carrying out a Preliminary Design Review of the correlator in Q1-2005.

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The construction of the large new RFI-shielded room for the new correlator will begin in FY2005. This room, which is part of the U.S. budget responsibility, will be built on the second floor of the VLA Control Building. Clearing out the floor area for the room will take place in Q2-2005 and assembly of the shielded room will occur in Q3-2005.

8. Continued procurement of large production orders of critical components.

During FY2004 the project began to place large production orders of critical electronic and mechanical components in order to reduce cost by economies of scale and also to prevent future obsolescence problems. In many cases these large orders are sufficient for the lifetime requirements of the EVLA, including both the quantities required to outfit 28 antennas and to maintain these systems for many years. These large procurements will continue in FY2005. In anticipation of the delivery of large quantities of electronic and mechanical components, a separate warehouse is being constructed at the VLA to store such items until the time comes to install them on the EVLA antennas. Planned large procurements for FY2005 include:

L and C-band feed horn centrifugal cast aluminum parts. Fiber-optic cables, multiplexers and demultiplexers for antenna outfitting. Data Transmission System formatter FPGA processors, backplanes, circuit boards, 8-bit digitizer chips and power supply components. Machined metal parts for module assemblies. Downconverter module tunnel detector diodes, band pass filters and circuit boards. M&C pre-assembled module interface boards. Ka-band receiver cooled isolators and noise diodes. L-band receiver 1-2 GHz post amplifiers. Antenna 48 volt DC power supply converters. WIDAR correlator RFI shielded room and HVAC units. U/X converter integrated circuit boards.

9. Procure components for, and begin construction of, the electronics systems required for the antennas to be outfitted in FY 2006.

Due to the long lead time associated with the procurement of components and the construction and testing of electronic modules, these activities must begin in the year prior to the installation of the equipment on an antenna. Therefore, in addition to the large production orders of components mentioned above in (8), the project will also purchase all of the remaining components required to build the electronic modules and receivers required for the antennas to be outfitted FY 2006. If accelerated funding is available six antennas will be outfitted in FY 2006. Construction of these electronic modules and receivers will begin in Q3-2005.

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Phase II - the “New Mexico Array”

This phase of the project will expand the resolution of the array by a factor of 10 by:

• Adding eight new antenna stations at distances of up to 300 km from the array center, to provide now-unavailable baselines between those in the VLA and those in the VLBA. • Adding fiber-optic links between the VLA and the inner VLBA antennas, and between the VLA and the additional new stations.

Also, addition of stations for a compact E configuration with baselines less than ~300 meters will provide increased sensitivity for imaging extended, low-surface-brightness objects.

A proposal for Phase II was submitted to the NSF on April 15, 2004. It is expected that Phase II activities in FY2005 will focus on providing such information as the NSF requires to complete its review and assessment of the proposal.

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6. NRAO Facilities

Green Bank Telescope

Figure 6.1. The Robert C. Byrd Green Bank Telescope.

GBT Operational Status

For essentially all of FY2004, the GBT was in full scientific operation. About 4900 hours of telescope time was scheduled for astronomy programs during the year, amounting to ~55% of total time, based on 24-hour per day observing. The remainder of the time went to commissioning of new capabilities, particularly for high-frequency instrumentation and development, and to scheduled maintenance. In the summer of 2004, structural inspections and painting of the GBT structure were performed. This activity requires a 10-hour work day, four days a week for 3-4 months to accomplish.

The GBT now has a full suite of observing instrumentation available for regular use by observers. This includes nine receivers ranging in frequency from 290 MHz to 50 GHz. Several detector backends are available, including the 256k-channel GBT Spectrometer, the older Spectral Processor, the Digital Continuum Receiver, and VLBA recorders. Several backends constructed by university groups are also installed at the GBT for pulsar and bi-static radar observing. These include the Berkeley-Caltech Pulsar Machine (BCPM), the Caltech-Green Bank-Swinburne Recorder II (CGSR2), the Green Bank Astronomical Signal Processor (GASP – constructed by U.C. Berkeley and U. British Columbia), and the Cornell-JPL Fast Sampler for bi-static radar observations. The Pulsar Spigot Mode of the Spectrometer was also brought into operation in 2004 and has already resulted in some spectacular results. This project is a collaboration of NRAO and Caltech.

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6. NRAO Facilities

A strategic goal for the GBT is to achieve efficient scientific performance at 3 mm wavelength. The Precision Telescope Control Project, which addresses this goal, has been structured to achieve interim improvements that allow efficient observations at increasingly shorter wavelength. In the past year, the project has achieved an offset pointing accuracy of less than 3 arcsecs RMS and a reflector surface accuracy of ~ 400 µm. This allows acceptable operation in benign conditions (low wind, nighttime observing) at 6 mm wavelength (50 GHz).

Key Science Results in FY2004

In this section we give a sampling of significant scientific results from the GBT that were reported in FY2004. This list covers quite a range of topics, and indicates the power and versatility of the GBT from imaging to point-source studies, and at wavelengths of ~1 meter to 1 cm.

Detection of HCN in a z=2.3 Galaxy - Hydrogen cyanide (HCN) emission has been detected in the z=2.2857 source IRAS F10214+4724 using the GBT. This is only the second detection of HCN in a high-redshift galaxy. HCN is a signpost of star formation, and F10214 clearly contains a starburst that contributes, together with its embedded quasar, to its overall infrared luminosity. The peak emission of the detected spectral line is about 0.45 mJy with a noise level of ~0.090 mJy. A new technique for removing spectral baselines in the search for weak, broad emission lines was utilized for this project. The HCN line was redshifted from its rest frequency of 88.6 GHz to ~27 GHz.

Figure 6.2. HCN emission from the z=2.3 object IRAS 10214+4724.

High-velocity HI gas about M31 - Several clouds of neutral hydrogen have been found around the Andromeda Galaxy, M31, using the GBT. These clouds may be the remains of the building blocks that originally formed M31 and may also be the analogs of the high-velocity clouds observed about the Milky Way. These clouds had eluded detection for many years; detections are now possible because of the clean beam and high dynamic range of the GBT.

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6. NRAO Facilities

Figure 6.3. GBT observations of HI clouds about M31 (orange), with a Westerbork Image of the HI gas in the disk of the galaxy shown in blue.

Observations of the Double Binary Pulsar J0737-3039 - Following the discovery at Parkes last year of the first double-pulsar binary J0737-3039, the GBT has been used to significantly improve the physical characterization of the system. This short-period system is the first example of a binary in which both stars are pulsars. It provides a unique laboratory for studies of general relativity and neutron-star physics. The GBT is able to observe the emission from both pulsars during most of the orbital period. A number of significant results were obtained in the initial observations. For example, it was found that that the eclipse profile of the faster pulsar, PSR J0737-3039A, by PSR J0737-3039B is asymmetric and is independent of frequency. The size of the eclipsing region was determined to be 18,600 km.

Galactic Center Lobes and Filaments - Images from the GBT have shown that giant lobes of material arising from the Galactic Center are part of the same superstructure and perhaps arose from an epoch of extremely energetic star formation (Figures 6.4 and 6.5).

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6. NRAO Facilities

Figure 6.4. Radio lobes arising from the Galactic Center.

Figure 6.5. Combined GBT and VLA images showing non-thermal radio filaments (NRFs)in the Galactic Center region.

New Interstellar Molecules Detected with the GBT - The GBT has been used to detect two new interstellar molecules, propenal (CH2CHCHO) and propanal (CH3CH2CHO). These are the first new molecules detected with the GBT. These molecules were detected in the star-forming region Sagittarius B2(N). The GBT was also used to observe the previously reported molecule propynal (HC2CHO). These molecules differ only in the number of hydrogen atoms present. The presence of these three molecular species in Sgr B2(N) indicates that simple hydrogen addition on interstellar grains may account for their formation. The Sgr B2(N) cloud appears to have ample energy sources to allow such grain reactions to proceed. This result suggests that successive hydrogen addition may be an important formation pathway for complex interstellar molecules. The GBT has offered a significant advance in astrochemistry studies owing to its high gain and clean beam, wide bandwidth and frequency-agile spectrometer, and high- sensitivity receivers.

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6. NRAO Facilities

Figure 6.6. Models of the two new interstellar molecules detected with the GBT, propanal, and propenal.

Operational Objectives for FY2005

In addition to sustaining ongoing operations, additional operational objectives for FY2005 are

• Increasing the amount of observing time available. • Concluding the azimuth track investigation and issuing repair contracts. • Enhancing data handling and telescope ease of use. • Enhancing and completing observing modes for the GBT Spectrometer, and drawing this project to an end.

These objectives are discussed in more detail in the following sub-sections.

Observing Time

We expect to schedule about 5000-5250 hours (55-60%) of observing time in FY2005. The high end of the range can be achieved if the final budget allows us to hire enough painters to do the required work in three months in the summer of 2005 (at 4 days per week, ~11 hours per day). In addition to astronomy time, we will reserve time for commissioning several major instruments, including the Ka-band receiver and associated Millimeter Down-converter, the Caltech Continuum Backend, further work on the Q-band receiver, and initial engineering tests of the Penn Array bolometer camera. In addition, considerable time will be devoted to continued development and testing of the Precision Telescope Control System. We are working to achieve further gains through the Ease of Use program that will allow the time budgeted for observing program changes to be reduced from 60 to <30 minutes. This should be possible through the planned introduction of a system that allows observer setup scripts to be composed and debugged prior to the start of observing, and by reducing and consolidating the applications needed to run an observing session.

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6. NRAO Facilities

Azimuth Track Program

The GBT azimuth track has exhibited premature and progressive deterioration. Several problems have been manifested: fretting wear on the mating surfaces of the wear-plate and base-plate assemblies, breakage of the bolts which hold down the wear plate, cracks on the ends of the wear plates, and crowning and cambering of the wear plates. The GBT engineering and maintenance team has developed mitigation methods that have extended the life of the track and kept the GBT operational. It has been clear for some time, however, that a significant modification or replacement of the track was likely. The existing track and proposed modifications have been studied in considerable detail through finite-element and analytical models, and through metallurgy and metrology, as required. A trial modification of one track joint was made in June 2003, has been tested through regular use of the telescope since then, and has been largely successful to date.

The study phase of track modification options will come to a conclusion in the first quarter of FY2005, a panel review will be held, and preferred design options will be chosen. Following further detailed engineering analysis and review of these options, we anticipate that contracts will be let no later than May 2005. Construction work will most likely occur in the summer of 2006, and conceivably sooner.

Data Handling and Ease-of-Use Improvements

Following the creation of the Single Dish Software Integrated Product Team, good progress has been made in the development and delivery of a consolidated FITS data product which enables data export into standard reduction packages such as CLASS and IDL. Application programming interfaces (APIs) were developed to configure and observe with the GBT in a manner that is easy and intuitive for astronomers. Plans for the continuation of these efforts in FY2005 are summarized in the chapter on Observatory Computing.

Spectrometer Development

The GBT Spectrometer is a powerful, versatile, and absolutely essential instrument for GBT spectroscopic science. Great progress has been made in the past year in implementing all of the principal autocorrelation modes, improving reliability, and introducing the pulsar spigot modes. In FY2005, three projects for the Spectrometer will be undertaken:

• Upgrade of the Long-Term Accumulator Cards with an entirely new design. This project is aimed at improving the reliability of the instrument. The design work and a successful critical review were completed in FY2004, but fabrication was postponed owing to lack of funds. Early in FY2005, we expect to fabricate the new cards. • Implementation of the cross-correlation mode of the Spectrometer. This capability will allow cross-correlated polarization measurements, as well providing a general-purpose cross-correlation capability. A cross-correlation test fixture has been under development in the past year, and the full implementation and testing of this mode should be completed in FY2005. • Refined implementation of the Pulsar Spigot Mode. The mode was released in “expert” mode in FY2004 and has already been extremely successful in producing new scientific results. This mode allows pulsar search bandwidths of as high as 800 MHz, at data dump rates as fast as a few microseconds. This large bandwidth, coupled with the large collecting area of the GBT, provides a huge increase in sensitivity for pulsar searches. The modes available will be extended, refined, and made easier to use in FY2005.

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With the conclusion of these projects in FY2005, we expect that the Spectrometer project will be finished, and that the instrument will be sufficiently robust and reliable that maintenance requirements will be significantly reduced. This should allow our digital engineering, software development, and scientific staffs to focus their efforts on other projects, including next-generation spectrometers and digital signal processors.

It should be noted that resources available for work on the GBT are limited. Operational improvements such as those described above compete with strategic development opportunities described in the following sections. There are considerable pressures for development and system enhancements that have already greatly exceeded our work capacity. In all cases, we attempt to choose priorities to deliver the best scientific return to observers, be it in an operational or strategic area. This will require some difficult choices.

Strategic Development Overview

Operational and project development priorities are initiated through discussions with Observatory Management, the scientific staff, and key users. Proposed priorities are presented to both the Visiting Committee and Users Committee for comment. The Operations and Development plans are described in some detail in the annual Program Plan. From there, plans enter the GBT project planning system, which includes a series of project reviews as appropriate, ranking in six-month strategic planning sessions, and allocation of specific effort in 6-week work cycles.

The GBT has several key instrumental assets that give it unique scientific capabilities. Although the GBT has a breadth of useful capabilities, the strategic plan seeks to optimize performance in the unique areas described below.

High-fidelity imaging - The unblocked aperture of the GBT significantly reduces its sidelobes, producing an exceptionally clean main beam. At the frequency of the HI line, for example, the first sidelobes of the GBT are ~30 dB below peak response, compared to the ~20 dB typical of symmetric antennas with blockage. In addition, the GBT’s active surface reduces the aberrations and misalignments which produce coma and astigmatism compromising observations at high frequencies. The high-quality optics of the GBT is one of its unique and powerful assets and represents a major step forward in capabilities.

Comparatively high angular resolution with sensitivity to total emitted flux and extended emission - The 100 m aperture of the GBT affords the comparatively high angular resolution of 740[arcsec]/ν [GHz]. Thus, at 100 GHz the GBT resolution is ~7". Furthermore, as a single dish, the GBT is sensitive to total flux from all angular scales. This is a key difference from interferometers, which can provide very high resolution but may be insensitive to extended emission. Sensitivity to total flux is a powerful asset for stand-alone science, and is also extremely powerful when data from a single dish and a synthesis array such as the VLA are combined to produce an image rich in the details of the radio source at all angular scales.

Wide field of view - The Gregorian optics of the GBT afford a wide field of view that is relatively free of aberrations. At 3 mm wavelength, the useable field of view is about 10 arcmin and could contain up to 10,000 beams or pixels in a fully sampled array. The focal plane can thus accommodate large-format imaging cameras. When coupled with the high fidelity, the comparatively high angular resolution, and the sensitivity to extended, low-brightness emission, it is evident that the GBT has unique potential as an

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imaging instrument. This is clearly a capability that we wish to foster through instrumentation and software initiatives.

High point-source gain at all frequencies from ~300 MHz to 115 GHz - The GBT has a physical collecting area of 7854 m2. This aperture, the unblocked optics design, the active surface, and precision control system combine to provide extraordinary gain and point-source sensitivity from low frequencies to, ultimately, 115 GHz. This gives the GBT high sensitivity to point sources such as pulsars, stars, and external galaxies. Because the GBT has high gain over three decades of frequency, it can be used to study cosmic phenomena that occur, or vary in nature, over a range of frequencies. For example, redshifted CO line emission may have lines that fall throughout the frequency range of the GBT, depending on the rotational transition and the redshift. A particularly valuable asset is the sensitivity of the GBT in the 26- 40 GHz range, to which J=1→0 CO lines are shifted for the supposed peak of star formation in the universe at z~2.5. Extragalactic continuum sources may emit in thermal free-free, synchrotron, or dust emission over ranges accessible to the GBT, which might then be used to separate the contributions of these phenomena to the continuum spectrum.

Comparatively low RFI contamination - The GBT is located in the National Radio Quiet Zone, a unique, national resource. Although Green Bank certainly experiences RFI, the natural topography of the area around the site in combination with Quiet Zone regulations continue to make it one of the best locations for radio astronomy in the world. For example, observations near the 1420 MHz HI line are largely free of contamination in Green Bank, whereas in certain parts of the world they have become almost impossible to carry out. We can exploit the Quiet Zone for numerous low-frequency projects and will continue to protect it vigorously.

As is evident from the description above, the information present in the focal plane of the GBT is extensive and unique in both the spatial and frequency domains. In overview, the strategic plan for the GBT is to develop the scientific capabilities to capture this information as completely as possible. The specific strategic objectives and projects or programs that address them are listed in Table 6.1.

Table 6.1 Strategic Objective Projects Addressing It Status Develop the high-frequency ¾ Precision Telescope Control System In progress capability and performance of ¾ 3 mm (68-92 GHz) Receiver the GBT to 115 GHz. ¾ Ka-band (26-40 GHz) Receiver Future ¾ Penn Array Bolometer Camera Commissioning ¾ Caltech Continuum Backends In Progress In progress Develop imaging cameras with ¾ Penn Array Bolometer Camera In progress increasingly large pixel ¾ Beam Forming Array Future formats at key bands, including ¾ 3 mm MMIC Array Future 21 cm, 1.3 cm, 1 cm, and ¾ 3CAM large format bolometer camera Future 3 mm. Develop ultra-wideband ¾ Wideband Spectrometer NSF proposal in frequency analyzers for preparation. redshift searches

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Tabel 6.1 (cont’d) Strategic Objective Projects Addressing It Status Mitigate the effects of RFI, ¾ Interference Protection Work In progress enhance the available spectrum ¾ Quiet Zone administration In progress in Green Bank, and increase ¾ MRI Grant Project In progress, and protection in the National recently renewed. Radio Quiet Zone. Develop observing strategies ¾ Dynamic and Queue-based scheduling Future such as dynamic and queue- development. based scheduling that will allow observing programs to take best advantage of the prevailing weather and RFI environment. Work to sustain and enhance ¾ Student Financial Support Program In progress the single-dish radio ¾ University-built Instrumentation In progress astronomy user community Program Held every two years through NRAO sponsored ¾ Single-Dish Summer School programs Ease of use by nonexpert ¾ e2e In progress astronomers ¾ Exportable FITS data In progress ¾ Application programming interfaces In progress

Although our strategic emphasis will be on these areas, the list is not inclusive of all activities, either developmental or operational. For example, we may work with university groups to develop next- generation pulsar observing back-ends. We will also devote resources toward upgrading existing instrumentation and data analysis, enhancing observer services, etc.

Strategic Development Objectives for FY2005

The section above provides the context for the long-range development program for the GBT. The specific projects underway in FY2005 are described in more detail below.

Precision Telescope Control System (PTCS) Development

The ultimate goal of the Precision Telescope Control System is to enable the GBT to work effectively at frequencies up to 115 GHz (wavelengths down to 2.6 mm). The PTCS Project is being executed in a phased approach that delivers specific intermediate improvements at 22 GHz (1.3 cm) and 43 GHz (7 mm). In December 2003 we reached our specific goal for Winter 2003/04 of acceptable performance at 7 mm. This is accompanied by excellent performance at 1.3 cm. Our goal for Winter 2004/05 is good performance at 7 mm and prototype operation at 3 mm (86 GHz). Initial operation up to 115 GHz will be provided by Winter 2005/06, with full operation, including an expanded suite of metrology instrumentation, following a year later.

The PTCS Project has made excellent progress over the last year. The project team is now stable, and consists of ~8 FTEs. As well as Richard Prestage (Project Manager), Kim Constantikes (Project Engineer), Jim Condon (Project Scientist), and Dana Balser (Commissioning Scientist), the project

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typically utilizes 3-4 FTEs of electronics division effort, and 2-3 FTEs of software development division effort, with the precise personnel and effort allocations agreed on a six-week basis through the GBT project planning system. Additional assistance is provided by staff from other sites on an occasional basis. Work on the PTCS project through the end of FY 2003 culminated in an extremely successful In- Progress Review (IPR) held in December 2003. The review material, presentations and committee reports for this meeting, as well as additional information on the project, are available at: http://wiki.gb.nrao.edu/bin/view/PTCS/WebHome.

Some of the major highlights of the project over the past year are as follows.

In the 2004 Program Plan we identified the completion of the antenna temperature-sensor system as a key component to deliver the intermediate goal of good Q-band (43 GHz) performance. This system has more than lived up to expectations. Twenty structural temperature sensors, providing ~0.1°C accuracy, have now been strategically located on the antenna alidade, feedarm, primary backup structure, and subreflector. During Fall 2003 we performed a series of commissioning observations to correlate antenna temperature gradients with pointing and radial-focus errors, and have developed a model which is capable of predicting and removing the bulk of these effects in real-time. In addition, these data have allowed us to disentangle gravitational and thermal effects, and so identify and remove systematic errors in both the traditional pointing and focus-tracking models. The so-called “dynamic corrections” for temperature gradients are now in routine use at frequencies above 10 GHz.

Our experience with the antenna temperature-sensor system has demonstrated that comparatively simple, short-time-to-development, targeted instrumentation can make a major contribution to antenna performance. Prior to installation, the offset pointing performance was around 3-4 arcsecond rms, the absolute (blind) pointing was 10 arcsecond rms, and there were systematic effects in both pointing and radial focus. The two-dimensional offset pointing under benign nighttime conditions is now < 2.7 arcsecond over timescales as long as 90 minutes; use of dynamic corrections can extend this performance well into daytime. Continuously tracking the half-power point of a calibrator for up to 30 minutes has demonstrated tracking errors of ~1 arcsecond under the best conditions. The absolute (blind) pointing performance is now ~4 arcsecond after allowing for a single initial pointing check. Using dynamic corrections, the blind radial focus accuracy is now ~2.5 mm under all conditions; the offset focus performance is significantly better than this.

Having made substantial progress on the pointing, we performed some more limited investigations of the surface efficiency during Winter 03/04. The aperture efficiency of the GBT at 43.124 GHz was measured using observations of 3C 286 in November 2003. It has a maximum ηa = 0.43 at elevation of 52 degrees, which corresponds to an rss surface error ~390 µm; this just meets our criterion for usable performance. The aperture efficiency falls off symmetrically at higher and lower elevations; the fall-off of beam efficiency is slower, as expected for large-scale gravitational deformations.

A second round of “out-of-focus” (OOF) and traditional (12 GHz phase-coherent) holography was performed in Spring 2004. This was extremely successful. Consistent results were obtained at the geostationary satellite elevation (~42°) from both techniques; both confirmed an rms surface error of ~400 µm dominated by large-scale errors. A number of attempts were made to test the holography results by performing back-to-back efficiency measurements on 3C286 and 3C279, with and without the corrections applied. Unfortunately, absolute efficiency measurements were prevented by uncertainties in receiver calibration and the poor weather conditions at the time of the observations. However, in all cases,

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the peak gain was improved by ~20-30%, the beam FWHM became closer to the theoretical value, and sidelobes were significantly reduced. We are therefore confident that we can use holographic measurements to substantially improve the surface accuracy of the antenna. The problems in determining absolute efficiencies have revealed a number of problems with the calibration of the Q-band receiver. These are currently under investigation and improved calibration methods are being developed. We are also developing procedures to allow easy measurement and correction of low-order aberrations (coma, astigmatism) using quick observations of astronomical calibrators, similar to those used to “peak” the pointing and focus.

Work on the Engineering Measurement System (EMS) was completed, as planned, in October 2003. The intent of the EMS was to process ground rangefinder data in near-real time to produce absolute (x,y,z) target positions in a routine way. This was envisaged both as a means of demonstrating the achievable potential of the rangefinders as well as performing precision surveys of various aspects of the telescope (e.g. deflection of the tip of the feedarm as a function of elevation). Although the EMS itself was extremely successful, the delivered performance of the rangefinders did not live up to expectations. Given the limited resources available and the great promise of the temperature-sensor system discussed above, work on the rangefinders was discontinued over the winter period. However, we are now reassessing the performance of the rangefinders as well as the other metrology instrumentation such as inclinometers and additional quadrant detectors (an angle-angle device) with a view to re-engineering these to develop an integrated system which will provide the accuracy required. This work will continue throughout FY2005.

We now believe we have methods, either in production use or in hand, to compensate for the gross effects of gravitational and thermal distortions. As we continue to address more subtle effects, the project will of necessity reacquire a considerable research component, and our plans may change as a result of continued investigations. Nevertheless, our broad approach through FY2005 will be as follows.

Development of a range of antenna instrumentation which can be implemented on appropriate timescales, and which provide direct information on relevant physical mechanisms affecting antenna performance, has formed a core component of the PTCS project since April 2003. The most important of these to date has been the antenna temperature-sensor system. We have also largely completed the installation of a suite of accelerometers and inclinometers, as well as a major redesign of the existing quadrant detector. This work will continue through FY2005.

We continue to refine the dynamic corrections system. Additional pointing runs have allowed us to refine the thermal models, and we have also started to incorporate the effects of bulk wind displacements, azimuth track irregularities and other repeatable departures from an ideal linear structure model. We plan to release a significantly refined and more flexible implementation of this system for the 2004/05 winter observing system, and we expect this will deliver close to 86 GHz pointing performance, at least under benign conditions. We will continue to use OOF holography and other astronomical techniques as described above to improve the surface efficiency, at least for gravitational effects. There is some evidence that the antenna is currently mis-collimated, and this may explain the observed rapid deterioration of performance under non-benign thermal conditions. A simple adjustment to the focus- tracking model might significantly reduce the severity of this effect.

We expect this combination of astronomical and engineering measurements will allow us to continue to make progress through FY2005, as they did during FY2004, to meet our target of prototype 86 GHz operation by Spring 2005. However, as noted, in parallel through FY2005 we will continue our system

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studies and explore potential redesigns of the laser rangefinder system with a view to phasing a revised version of this back into operation during the following year.

Other Strategic Initiatives

Ka-band Receiver - This receiver covers the 26-40 GHz (1 cm wavelength) range. It is a dual-beam, dual–polarization receiver with pseudo-correlation (continuous comparison) architecture. This architecture allows very fast switching between the two beams and effectively removes 1/f noise in broadband continuum measurements. This receiver covers the frequency range at which 1 → 0 CO (115 GHz rest frequency) line will be shifted for galaxies at a redshift of ~2.5, which is the supposed redshift of the peak of star formation in the universe. The GBT has high sensitivity and works extremely well in this frequency range. The receiver will also be used with the Caltech Continuum Backend to measure the emission from very weak radio sources, which will allow much more accurate analysis of cosmic background fluctuations.

The Ka-band receiver was largely completed in FY2004 and underwent initial engineering checkouts in the spring of 2004. Full astronomical commissioning will resume in the first quarter of FY2005, and we expect to commence regular use of the receiver in the 2nd Quarter of FY2005.

Caltech Continuum Backend (CCB) - The CCB is a collaborative project between Caltech and NRAO to develop a fast-switching high-sensitivity continuum backend for use with the Ka-band and future W-band (3 mm) receivers. The backend is capable of analyzing essentially the full bandwidths of each receiver, with the bands broken into three or four sub-bands to allow some spectral analysis. The initial scientific driver for this instrument is to allow sensitive detection of weak radio sources so that cosmic background fields can be corrected for point-source contamination. This will allow more accurate analysis of data from the Cosmic Background Imager and other anisotropy projects. In the longer term, this backend will facilitate sensitive observations of a variety of continuum sources in the 1 cm and 3 mm bands. The CCB was funded as part of the Observatory’s University-built Instrumentation Program. Caltech and NRAO have collaborated closely on this instrument and both institutions have undertaken significant work packages as part of the project. The CCB project team is presently laying out the circuit boards, writing software for the field-programmable gate arrays (FPGAs), and procuring components. We expect the CCB to be completed and commissioned in FY2005.

Penn Array Camera - The Penn Array is a 64-pixel bolometer camera for the 3 mm band that is being developed by a consortium of the University of Pennsylvania, NASA-Goddard, NIST, Cardiff University, and NRAO. This project is also being funded largely through the NRAO University-built Instrumentation Program. As noted in the discussion of strategic goals, the GBT has great scientific potential in both the imaging and millimeter-wave science areas. The Penn Array will be the GBT’s first major instrument to combine both of these assets. The Penn Array should serve as a pathfinder toward much larger format arrays, but is an ambitious and extremely powerful scientific instrument in its own right. The camera has an 8x8-pixel array with full spatial sampling, i.e., it will not be necessary to step the position of the telescope to achieve Nyquist sampling within the field-of-view of the array, which is approximately 30" x 30". The angular resolution will be about 8" per pixel. The detector array is made up of state-of- the-art Transition Edge Sensors (TES’s) with SQUID multiplexers, all cooled to a cryogenic temperature of 0.25 K. The sensitivity of the array should be better than 500 µJy/√sec per pixel. This extraordinary sensitivity will open a number of areas of investigation, including observations of the Sunyaev-Zeldovich Effect, detection of galaxies with extremely high redshifts, observations of trans-Neptunian and other weak solar-system objects, etc.

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The Penn Array successfully passed a critical design review in FY2004. Cryogenic systems were built and tested, and the optical system was completed. The camera is largely assembled in the lab and awaits delivery of the detector arrays. First engineering tests on the telescope should occur early in 2005, and the camera should be available for production astronomy in the winter of 2005/2006. The optics and the detector layout are shown below in Figure 6.7.

Figure 6.7. (Left) A cutaway depiction of the optics and cryostat for the Penn Array. (Right) The detector circuit board and mechanical mockup of TES detectors.

Pulsar Initiatives - In several important respects, the GBT is becoming the most formidable pulsar research facility in the world. The large collecting area and full steerability of the dish give it the inherent sensitivity and versatility for important studies. The suite of instrumentation for pulsar detection is also impressive. The Spectrometer Spigot Mode allows super-sensitive pulsar search modes with detection bandwidths up to 800 MHz. The system can sample at rates of a few microseconds and in FY2005 should have cross-polarization modes available. Users have also brought several important instruments, including the CGSR2 and GASP machines, both of which are powerful cluster-computing systems for realtime coherent de-dispersion pulsar observations. Since it is clear that users are developing significant instruments, the NRAO hopes to coordinate and facilitate this work to the best end for the scientific community. Discussions are presently underway for coupling CGSR2 and GASP to effectively double the analysis bandwidth of these systems.

Wideband Spectrometer Initiative - A natural scientific target of the GBT is the detection of very high- redshift molecular line emission from the earliest galaxies. The supposed peak of star formation in the universe at z ~ 2.5 places the 1 → 0 CO line in the 26-40 GHz Ka-band region, at which the GBT is uniquely sensitive. Higher-lying CO lines will sample higher redshifts, and the 3 mm window will

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eventually be available for sampling yet more lines and redshifts. Figure 6.8 shows the accessibility of important CO and CI lines at a range of redshifts using GBT receivers.

Figure 6.8. CO and CI sky frequencies as a function of redshift, with overlays of GBT receiver coverage.

Since photometric redshifts have large uncertainties, a very wide-bandwidth spectrometer that could simultaneously sample a range of redshifts would be an extremely powerful and scientifically valuable instrument. For some years, the NRAO has explored these possibilities with Professor A. Harris of the University of Maryland. Professor Harris has developed a wideband spectrometer (WASP2) that is in successful use already at the Caltech Submillimeter Telescope. Prof. Harris is presently developing an NSF proposal for the construction of such a backend for the GBT. The NRAO will be a co-investigator on the proposal, which should be submitted early in FY2005. This instrument would be constructed over the following two years and would be a major scientific addition to the GBT.

RFI Mitigation Program - The Observatory’s RFI mitigation program works at several levels. Within Green Bank Operations, the Interference Protection Group seeks out and mitigates sources of RFI in equipment, utilities, etc., both on site and in the vicinity of the observatory. We aggressively administer the National Radio Quiet Zone to preserve the unique protection it affords. Despite these efforts at RFI containment, there are still significant sources of RFI arising from ground-based transmitters outside the Quiet Zone, from aircraft, and from satellites. A strategic development program to mitigate these sources of RFI has been funded through an NSF Major Research Instrumentation (MRI) grant to R. Fisher and collaborators. This grant has just been renewed and will focus on “smart blanking” techniques that remove pulsed signals emitted by ground-based radar and airborne distance-measuring equipment, and on adaptive-canceling techniques that will remove continuously transmitted signals from aircraft and terrestrial sources. The project has already succeeded in removing interference from an aviation radar

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system in Virginia and from distance-measuring transmissions from aircraft. The work done as part of this project is of great benefit to the field of radio astronomy in addition to specific benefits to GBT observations.

Long-term Objectives and Development Program

The preceding text describes operational and strategic objectives for FY2005. The following material describes longer-term strategic initiatives designed to extend the scientific capabilities of the GBT. These projects are envisioned to offer dramatic advances in capability.

Large-Format Imaging Systems

Among of the GBT’s greatest strengths are its imaging characteristics. The unblocked aperture provides a high-fidelity beam, the Gregorian optics allow a wide field-of-view, the large filled collecting area provides high sensitivity to both point-like and extended emission, the large aperture provides comparatively high angular resolution, and the precision control system allows for operation in the 3 mm window as well as at longer wavelengths. Most of the first-generation GBT receivers are single- or two- beam systems. A next generation of multi-beam receivers could increase imaging speeds by factors of 10s to 1000s, with the corresponding return in scientific results. With speed improvements of this magnitude, it is obvious that many projects would be possible that could not be contemplated without them. Such instruments would allow much larger fields to be imaged to much greater sensitivity and would allow us to take much better advantage of the best observing weather for observations at the higher frequencies. Instruments of this type may require a significant investment in effort and capital, but then will still amount to only a very small fraction of the total capital investment in the facility. Thus, such instruments should pay great returns in science and will allow the community to get full value from the facility. The imaging instrumentation projects we are planning are described in the following sections.

3CAM Bolometer Array - Perhaps the most dramatic advance in radio-astronomy technology in recent years has come in the ability to fabricate millimeter-wave bolometer cameras with thousands of pixels. The technologies enabling this advance are integrated Transition Edge Sensor (TES) bolometers and SQUID multiplexed readouts. It is now possible to make wafers each containing hundreds or thousands of TES bolometers. The associated SQUID readouts can be bump-bonded on a second wafer or, in the case of a small array, placed on another discrete wafer. The Penn Array Camera, which should be delivered to the GBT in 2005, is based on exactly this technology. The Penn Array Camera has a modest 64 pixels, but we believe that a camera for the GBT that is 100 times bigger, i.e., 6400 pixels, is technologically feasible and practical even now. Such a camera on the GBT would have astounding scientific capability. For example, it would be able to image an entire Sunyaev-Zeldovich cluster in a single pointing.

If initial results from the Penn Array Camera are positive, as we fully expect them to be, we will begin organizing for a large-format 3 mm bolometer camera, which we are calling 3CAM. This will be a major project that will require expertise in advanced bolometers, cryogenics, optics, packaging, and data reduction. Such a project is probably best done as a consortium effort with experienced universities and development labs. Several groups have already expressed interest in this project.

Beam-forming Array - Observers also desire a dramatic improvement in centimeter-wave imaging capability for both spectral-line and continuum projects. A very promising technology under study at NRAO is a beam-forming array. Concepts for a 21 cm (L-band) array that would allow rapid imaging of

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neutral hydrogen (HI) emission, hydroxyl (OH) lines, and wide-field searches for pulsars have been proposed. With beam-forming arrays, a collection of planar feeds and receivers sample the electric field in the focal plane. Combination of the outputs of each of these feeds with proper weighting will allow a fully sampled image of a region of the sky. One can, in principle, control the shaping and sampling of the response on the sky and achieve better efficiency than with a conventional feed system. One can also correct for off-axis optical aberrations, which will allow the beam-forming array to be placed at the GBT’s prime-focus position.

There have been some successful proof-of-concept demonstrations of a beam-forming system already. Nevertheless, there is some significant technology development required for a practical instrument having sensitivities competitive with current discrete-feedhorn receivers. Specific areas requiring work are feed design, integrated receiver components, cryogenic strategies, and signal processing. Some of these areas are under investigation now, but most await additional staff and capital resources.

MMIC 3 mm Spectroscopy Camera - The 3CAM bolometer camera should provide a dramatic advance in 3 mm continuum imaging, but important spectral-line imaging capabilities are also desired. For example, a 3 mm image of HCN, CS, CN, or CO emission with ~6-8 arcsecond angular resolution over a ~10 x 10 arcminute field-of-view would fully image most Galactic star-formation regions and provide a complete picture of large-scale kinematics of the region, possible magnetic-field structure through polarimetry, and could identify new protostars. Interesting sites could then be examined in more detail by ALMA or CARMA.

MMIC arrays of HEMT amplifiers with 100 or more feeds now seem practical and are being developed at JPL and elsewhere. More technology development of the receivers is required, and we must also develop a cost-effective spectrometer with adequate bandwidth and resolution for so many beams. We are presently limited by resources but hope to begin this program in the coming few years.

Software Development for Imaging Systems - In addition to hardware and signal-processing development, we must also develop image-processing software for the systems described above. We must be able to calibrate accurately across the imaged fields and remove the effects of the atmosphere. Because the data volume is likely to be huge for these new-generation instruments, it is important that the data processing be amenable to automated batch processing (pipelining). We are approaching these problems on an Observatory-wide basis to achieve the most efficient and broadly based development possible.

Receivers Optimized for Spectral-Baseline Performance - As the demands grow for wider spectral bandwidths and higher sensitivities, the requirements on instrumental stability also grow. Through a concerted engineering and testing program over the past two years, GBT spectral baselines are now generally good and allow most spectral-line projects to proceed well. The most demanding programs with weak, broad lines may, however, still be handicapped by baseline performance. The team investigating these effects believes that we are approaching the point of diminishing returns in attempting to further improve baselines with the existing receivers and IF chains. Additional gains are likely to require a different and simplified architecture for which the radio frequency (RF) components have a higher degree of integration (with less opportunity for resonances and mis-matches), shorter and less- complex IF down-conversion chains, digitization very close to the receiver, etc. This requires a new receiver and IF architecture. Concepts have been proposed for this and some work has been undertaken. It has been suggested that we try to implement these concepts in a new receiver operating at X-band (~8- 10 GHz).

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Wideband Spectrometers - As described in the FY2005 strategic initiatives, we expect that Prof. A. Harris will submit a proposal for the development of a wideband spectrometer for redshift searches. This instrument will cover most of the 26-40 GHz receiver band at a spectral resolution of 13 MHz (~150 km/s at Ka-band) or better. The effective resolution will likely be optimized in software so that there is a “matched filter” to the galaxy emission. Since this instrument is based on a proven prototype, we have considerable confidence that it will be successful on the GBT.

In the longer term, we would like a technology that would allow wideband spectral analysis for multiple receiver chains, so that one could perform wideband spectroscopy with a multi-beam receiver. This would allow blind redshift searches over an extended spatial field. The GBT may well be the most sensitive instrument in the world for such observations, and this capability could be extremely important to cosmology and early galaxy formation studies. It should be noted that there is unlikely to be a confusion limit in these surveys since multiple objects in the GBT beam will almost always be separated in frequency owing to their different redshifts. A multi-beam redshift machine will require technology development to achieve an effective instrument at a practical cost.

Advanced PTCS projects and Adaptive Optics - Over the course of the next two years, we expect to achieve good 3 mm observing capability with the GBT, a major strategic goal for the facility. There will almost certainly be refinements to this system that will improve performance and the range of environmental conditions (wind, thermal) for which efficient observations are possible. It is also likely that a second generation of compensation techniques and instrumentation may be desirable. For example, it may be possible to remove the effects of radio “seeing” in the atmosphere through sensing and adaptive-optics techniques. This might be implemented through a water-vapor radiometer system that sweeps the sky, coupled to a two-axis active tertiary. Techniques whereby the primary surface profile is adjusted for best performance by real-time optimization of the point-spread function using the Penn Array Camera may also be possible. Enhancements that improve surface accuracy and pointing or extend useable observing conditions should pay significant dividends in science.

GBT Long-Range Development Budget

The development budget for the GBT in FY2005 and a projection for the subsequent two years is given in the following table. At present, Green Bank Operations has approximately 27 FTEs available for development work after operational duties are satisfied. This number includes those people assigned to Green Bank Operations but who are physically located at other NRAO sites. The projects to be undertaken in FY2005 have been scoped to balance the effort and capital in the operating plan.

Consequences of Presidential Request Level Funding for GBT Activities

The Presidential Request Level funding for the GBT is well below the requirements to sustain on-going operations or to carry out the planned development program. PRL funding would require a lay-off of several staff members. It would require that the GBT Student Support Program be terminated entirely. RFI reduction efforts would be curtailed. The capital equipment budget to support the Precision Telescope Control System, the GBT's highest development priority, would be cut by a third. Software effort would be reduced, which would seriously slow the data reduction and ease of use initiatives, and the GBT's ability to participate in Observatory-wide e2e development. Since project staffing is under stress even at the Mission Requirements Level, a reduction to the PRL level may have negative consequences beyond those mentioned above.

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Table 6.2 GBT Development Program Estimated Costs1 FY2005 through FY2007 Mission Requirement Levels Fiscal Year FY2005 FY2006 FY2007 Project Cost k$ FTEs Cost k$ FTEs Cost k$ FTEs

GBT Development Plan - Active Azimuth Track Investigations2 150 2.0 1.0 Precision Telescope Control System3 117 8.0 125 8.0 50 5.0 Spectral Baseline Improvements 0.5 Data Handling Improvements3 3.5 3.5 2.0 Ease of Configuration & Use4 2.5 1.0 1 cm Rx (26-40 GHz) 1.0 3 mm Rx Module 1 (68-92 GHz) 15 0.5 10 2.5 RFI Suppression Program 10 2.5 15 2.0 15 1.5 Spectrometer Upgrades 30 1.5 Rx and System Upgrades 1.0 50 1.0 50 1.0

Future Program Conventional Receiver Development 3 mm Rx Module 2 (90-116 GHz) 50 0.5 25 2.0 Prime Focus HI Receiver 25 1.0 75 1.0 Observing Efficiency Dynamic & Queue-based Scheduling 0.5 2.5 2.0 Receiver Turret Rotator Upgrade 75 1.0 Atmospheric cancellation & advanced PTCS 7 mm (Q-Band) Tertiary Mirror 50 2.0 10 1.0 Beam-Forming & Spec. Baseline Initiatives Next-generation X-Band Rx 15 0.7 50 2.0 25 2.0 Digital Signal Processing Development 25 1.0 50 2.0 Millimeter-wave Imaging Systems 3CAM Bolometer Array 25 1.0 500 8.0 Total NRAO Internal Development: 337 24.2 500 30.0 800 27.5

University-built Instrumentation Penn Array Bolometer Camera 85 1.50 85 1.00 Caltech continuum backend 1.00 Future Projects Wideband Spectrometer5 1.5 0.25 1.5 0.25 Total University-built Instrumentation 87 2.8 87 1.3 0.0 0.0

Totals: 424 27.0 587 31.3 800 27.5

Footnotes: 1Capital and FTE values for future projects are very rough estimates for planning projections only. 2To be funded from the special Azimuth Track Repair account. 3Includes staff contributions from other Observatory units. Project includes continuation to pipeline or batch processing development. 4Includes remote observing development. 5We anticipate that the bulk of expenditures for this project will come from an independent grant.

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Very Large Array

VLA Operational Status

The VLA consists of twenty-seven 25 meter antennas arranged in a Y-shaped configuration, with nine antennas on each 20 km arm. The antennas are transportable along a double rail track and may be positioned at any of 72 stations. In practice, the antennas are rotated among four standard configurations that provide maximum baselines of 1, 3, 11, and 36 km. Additional “hybrid” configurations with a long northern arm are used to provide optimal sampling of sources in the south. Reconfigurability provides the VLA with variable resolution at fixed frequency or fixed resolution at multiple frequencies.

The VLA supports eight frequency bands, most of which can be remotely changed by means of subreflector rotation. (The 74 MHz system consists of dipoles which are mounted periodically for short campaigns, then removed, due to minor impact on the aperture efficiency at some of the other frequencies.) The following table summarizes the current parameters of the VLA receiving systems. The VLA has full polarization capability in all continuum and spectroscopic bandwidths ranging from 50 MHz to 195 kHz. Within certain total-bandwidth limitations, 512-channel spectroscopy is supported in all bands.

Table 6.3

VLA Receiving Systems

Frequency Tsys Amplifier (GHz) (K) 0.070 to 0.075 10001 Bi-Polar Transistors 0.308 to 0.343 150 GaAsFET 1.34 to 1.73 33 Cryogenic HFET 4.5 to 5.0 45 Cryogenic HFET 8.0 to 8.8 31 Cryogenic HFET 14.4 to 15.4 108 Cryogenic GaAsFET 22.0 to 24.0 55 Cryogenic HFET 40.0 to 50.0 95 Cryogenic HFET 1 Tsys includes Galactic background.

Accomplishments in FY2004

Observing and User Programs

Over a number of years, the amount of scientific observing time used on the VLA has remained very stable at approximately 76% of the number of hours in a year. Despite significant construction on the EVLA, the VLA maintained scientific observing time at 76.4% over the first 10 months of FY04. The percentage of downtime was increased somewhat over previous years, at about 6% rather than the

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traditional 4%. This was largely due to the fact that the EVLA prototype antenna (Antenna 13) was unavailable for scientific observing for a large portion of the year; just having one antenna down counts as 3.7% downtime. The VLA has continued its decades-long tradition of being one of the most scientifically productive telescopes on Earth. Figure 6.9 plots the number of refereed publications for VLA and VLBA over nearly 30 years, and shows that the VLA has been at a steady state of 150-200 publications per year for almost two decades.

Figure 6.9. Refereed publications using the VLA and VLBA, over the last 25 years.

Observing on three Large Proposals began in FY04, following evaluation and recommendations from an external Large Proposal Review Committee. The proposals that were allocated time are “Virgo: A Laboratory for Studying Galaxy Evolution” (240 hours in C configuration); “VLA Low-frequency Sky Survey” (690 hours in B and BnA configurations); and “Stuff that Matters: The Physical Conditions of the Interstellar Medium in Nearby Galaxies” (293 hours in B, C, and D configurations as well as the associated hybrids). To maintain the ability for individual investigators to perform smaller science programs, as well as to make low-frequency (74 MHz) observations at night time wherever possible, all three of the accepted Large Proposals are being carried across two of the 16-month VLA configuration cycles and will not be concluded until FY05.

During FY04 we did the first observing under a joint proposal process between Chandra and the VLA/VLBA, aimed largely at the VLA. Four proposals were accepted in FY03, for a total of 40 hours, for Chandra cycle 5, which roughly coincides with FY04. Scientific results are still pending.

The NRAO has implemented a new set of policies for “Rapid Response Science,” which incorporates observations of known transients, exploratory science that does not fit normal proposal deadlines, and true targets of opportunity. These policies are intended to provide better response to rapidly moving developments in modern astrophysics, including instruments that are designed specifically to investigate the time domain (e.g., gamma-ray burst telescopes and optical-transient searches). The new procedures went into effect at the beginning of FY04. In the first 10 months, there were 18 accepted VLA proposals

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(and 5 VLBA proposals) for targets of opportunity or exploratory science under the new rules. Proposals for known transients are reviewed by the standard VLA/VLBA referees at the normal proposal deadlines, then observed if specific triggering criteria are met. We do not keep a count of “accepted” proposals in this category since many are never triggered.

In February 2004 the NRAO co-sponsored a conference on “X-ray and Radio Connections” in Santa Fe, NM. The purpose of the meeting was to bring together theorists, X-ray astronomers, and radio astronomers to discuss similar multi-wavelength physics in many areas. The meeting, co-sponsored by the Chandra X-Ray Center, Goddard Space Flight Center, Los Alamos National Laboratory, and NRAO, was attended by more than 110 scientists from all parts of the world.

One hundred forty-eight students attended the Ninth Synthesis Imaging Summer School from June 15 through June 22, 2004 on the campus of New Mexico Tech. This very successful school on aperture- synthesis theory and techniques, at a level appropriate for graduate students in astrophysics, is now held as a biannual event in Socorro. Practical tutorials demonstrating data collection, calibration, and imaging of VLA, VLBA, and millimeter interferometry data, as well as proposal writing, are presented.

Another successful summer-student program in Socorro was held during the summer of 2004. Seven undergraduates were hosted by the NSF REU program, and one undergraduate and three graduate students were hosted by NRAO Operations. In addition four visitors (including a graduate student, an undergraduate, and a postdoctoral fellow) were in residence in Socorro on long-term visits (at least several weeks).

High-Frequency Systems

After a number of years of effort, FY04 saw the completion of the new 43 GHz systems on the VLA. Holography on all VLA antennas has been completed, with typical 43 GHz aperture efficiencies raised to 40% or higher. (The VLA initially was designed only to work up to 22 GHz, so this has been a substantial multi-year effort.) We also have completed replacement of all older 22 GHz amplifiers by new low-noise amplifiers. The typical system temperature at 22 GHz now has been reduced by a factor of 2-3, providing great benefits for the ~1000 hours of observing that use this frequency band each year.

Water-Vapor Radiometry

Prototype water-vapor radiometers using the existing 22 GHz HEMT (High Electron Mobility Transistor) receivers were tested on two VLA antennas during FY03 and FY04. These devices work by measuring the antenna temperatures at three closely spaced frequencies at the peak and on either side of the water line, allowing a solution to be derived for both the liquid water content and the water-vapor content of the atmosphere; it is the water vapor that affects the interferometric phase. Significant improvements in phase stability have been demonstrated using the two prototype systems, after using the measured interferometric data to solve for a scaling factor from noise power to phase, and then applying the phase corrections to the actual data. Figure 6.10 shows the improvement in phase for one of these test experiments.

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Figure 6.10. Uncorrected phase (red, middle), scaled WVR output (green, bottom), and the phase after being corrected using the scaled WVR output (blue, top) for a baseline length of 2.5 km, sky cover 50-75% with forming cumulus clouds, and an observing frequency of 22 GHz. Note that application of the scaled WVR data reduces the rms phase(relative to the mean) from 70 degrees to 27 degrees, greatly improving the coherence of the interferometry data.

In FY04 a three-phase project plan was developed to construct a new compact water-vapor radiometer using MMIC (Monolithic Microwave Integrated Circuit) technology, whose implementation now has begun. Further details are found in the FY05 plans.

Infrastructure

The ALMA and EVLA projects have increased the demand for office and work space at the Array Operations Center (AOC) and VLA site. A new building on the New Mexico Tech campus was leased, and the purchasing, fiscal, business, and human resources groups were relocated to the new building to make office space available for project personnel in the AOC. The interior of an existing building at the VLA site was renovated to house the EVLA fiber group. A warehouse is being erected at the site to store equipment and materials purchased for the EVLA project. The warehouse will be converted to operations work space when the project is complete.

In FY01 a program was begun to install new elevation encoder systems to improve the pointing performance of the VLA antennas. Tests show that the pointing errors have been reduced well below the overall goal of 6 arcsecsecond for blind pointing accuracy. So-called “reference pointing” has been implemented previously to improve pointing performance on time scales of a few minutes to an hour or so. However, the old encoders caused cyclical (with respect to azimuth and elevation position) pointing

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errors that could not be corrected by reference pointing. The encoder-replacement program has been completed in FY04 with the installation of systems on antennas 14 and 24, and the desired short-term pointing accuracy has been achieved.

The bad azimuth bearing on antenna 14 was replaced in May 2004, making this the eighth VLA azimuth bearing to be replaced.

In 1998 an internal inspection of the VLA track system found one-third of the railroad ties to be past their service life. To replace these ties and overcome their deterioration rate, the ties need to be replaced at a rate of 5000 per year for 20 years. Infrastructure funding in 2001 enabled the purchase of a three-year supply of ties and ballast, intended to last through the end of FY04. During FY03 and FY04, the tie- replacement program was slowed somewhat due to the lack of personnel resources. Consequently, the supply of ballast is likely to last well into FY05, although there are only about 1000 ties on hand at the end of FY04. An annual infusion of $300,000 in materials is now needed to sustain the replacement rate of 5000 ties per year. Over the long term, failure to maintain the track could require discontinuing the use of the A (largest) configuration as a safety measure.

During FY04 we significantly enhanced our training program for accident response at the VLA site. This is an important aspect of safety for our employees because the VLA is located 50 miles from the nearest hospital. We now have three emergency medical technicians (EMTs) and 14 first responders on staff at the VLA, with another employee who is scheduled to complete the EMT training requirements early in FY05.

Computing Infrastructure

Rewiring of the AOC building from 10/100 Mbit twisted-pair Ethernet to 1 Gbit fiber-optic Ethernet was completed in FY04. Migration of existing scientific-staff systems to the new network is essentially complete. The new network infrastructure allows transfers from the online archive at approximately 60 MB/s (Megabytes per second) over the previous 1 to 6 MB/s. Prior to the rewiring, reading data from Exabyte tape was actually faster than from the online archive for most local systems.

Plans for FY2005

Approval of Phase 1 of the EVLA Project implies that the VLA will be an exciting, forefront astronomical instrument for at least the next two decades. As such, it should be the centerpiece of an effort to make NRAO-New Mexico the world’s forefront facility for centimeter- and decimeter- wavelength interferometry. The EVLA and VLBA will be the existing instruments in this “center of excellence,” and possible future instrumentation may include the New Mexico Array (Phase 2 of the EVLA), the Long Wavelength Array, the Frequency-Agile Solar Radiotelescope, and ultimately the Square Kilometer Array.

Phase 1 of the EVLA Project focuses on enhancements of the electronic instrumentation, which are described in the separate EVLA section. However, this instrumentation rests on the present VLA infrastructure, which must also be a focal point in the upcoming years. The third component of a program to make the EVLA reach its unique potential is the establishment of the above-mentioned scientific center of excellence, centered around the EVLA. This will include enhanced user computing services, many of which are described in the section on the Interferometry Software Division, as well as additional scientific services for users. These future services, which are necessary in order for the EVLA to reach its scientific

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potential, will require long-term augmentation of funding; the present operations budget supports only the activities that already are carried out for the VLA, and not the more expansive vision. Below, we outline the plans for FY2005, assuming the Mission Requirement Level NRAO budget. We point out some areas in which budget augmentation would enable a more complete realization of the long-term vision.

Observing and User Programs

In FY04 there has been little decrease in the VLA capability due to EVLA development. However, in FY05 we expect a more significant degradation. For substantial amounts of the year, we expect to have a maximum of 25 antennas available for scientific observations, rather than the normal maximum number of 27. To cap costs, it is possible that the trigger for technician “callouts” in the off hours will be changed from the current “three-antenna rule,” in which callouts are made only when more than three antennas are off line. It is likely that we will implement a “four-antenna rule” for part of FY05, so that callouts would occur only when the array is down to 22 working antennas. This implies a significant degradation in the science for some projects, since both the sensitivity and aperture-plane coverage are proportioned (approximately) to the square of the number of working antennas. The necessity of testing antennas that have been modified to EVLA standards implies that the amount of scientific observing time also may be reduced or that subarrays of ~3 antennas may be taken out of the VLA for testing during some scientific programs.

A second round of joint VLA/Chandra proposals was held for Chandra Cycle 6, to be observed primarily in FY05. During FY05 we expect the VLA to observe about 200 hours in support of these joint proposals.

In FY05 we will continue our successful summer student program. Typically, we host 6-8 summer students in the NSF Research Experience for Undergraduates program, and 4-6 more funded by NRAO. About half the projects involve VLA science, while the other half involve VLBA research.

The U.S. radio-astronomy community has attracted fewer students in the last several years, due largely to faculty members who spend an increasing amount of time observing with NASA observatories and receive funding along with their observation time. For the VLA and the VLBA we would like to add a student-support program that would fund graduate students to do research in the context of accepted proposals on the VLA. Such a program has been very successful for the GBT and should be expanded to the VLA as well. In particular, we expect that the VLA would be an ideal training ground for future users of ALMA. A budget augmentation would be needed to meet the required budget of $150K in FY05 and $250K to $300K in succeeding years, which would permit funding of approximately seven students in FY05 and 11-14 students per year thereafter.

Scientific Transition

A requirement for the EVLA project always has been that antennas that have been modified as part of the EVLA also can observe in VLA modes along with un-modified antennas. In FY05 we will be operating only with the old VLA correlator, so this hybrid observing method will be quite important. Not all modified antennas will have working receivers at all VLA frequencies, so the capability of the VLA will be degraded in some regards. (See discussion in the preceding subsection.)

A group has been formed to develop a detailed plan for operational and scientific capabilities during the transition from VLA to EVLA. By January 2005 this EVLA transition group will have a science working

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plan with dates, milestones, and personnel requirements for the transition from VLA to full EVLA operation. This plan is intended to evolve with time after that but should provide a framework in which we can work. During the rest of FY05, with input from our external committees, we will work to fill out and adjust the plan as we see more clearly into the future.

During FY05 we will experiment with dynamically scheduling the VLA, probably using the ALMA scheduling software. It is our intention for the EVLA to be dynamically scheduled. We have some experience with dynamic scheduling of the VLBA, but the variables controlling the decision process are different with the EVLA and we need to get some experience. The first major experiment is currently planned to take place during the June 2005 reconfiguration from CnB to C configuration.

High-Frequency Systems

One of the outcomes of the EVLA project is the relocation of the 43 GHz feeds around the feed rings on the EVLA antennas. The years-long effort at 43 GHz holography on the VLA has resulted in panel adjustments on the primary antenna surface that compensate for surface irregularities of both the primary reflector and the subreflector. Although the primary reflector has been the larger contributor to the loss of aperture efficiency on most VLA antennas, the subreflector clearly makes a non-negligible contribution in some cases. Therefore, the relocation of the feeds will negate some fraction of the aperture-efficiency improvement that was gained in the past. After a significant number of antennas have EVLA production hardware installed, we plan to resume the holography program to (again) maximize aperture efficiency at the highest VLA frequencies. We anticipate re-starting the holography program in earnest either late in FY05 or early in FY06, when the VLA is in compact configurations for the fall and part of the winter.

Water-Vapor Radiometry

During FY05 we will complete Phase I of a plan to develop a new compact water-vapor radiometer based on MMIC technology, to reduce tropospheric path-length fluctuations in VLA data. This phase involves construction of a single-channel prototype device. Initial design of this prototype and hardware acquisition took place in FY04. In FY05 the primary cost of Phase I will be approximately 0.35 FTE personnel to finish construction and test the single prototype. Phase II would require four 5-channel devices to enable full testing of the capability of these devices to improve the coherence of VLA data. The cost of Phase II, approximately $22K for hardware and 2.1 FTEs, ideally would be split between FY05 and FY06. Phase III is the full implementation of the water-vapor radiometers on the VLA/EVLA and would cost $180K for parts along with 6.6 FTEs. (Note that 20% contingency is included in all the numbers for Phase II and Phase III.) Phase III would be spread over several years and would be complete at the time of completion of the EVLA construction project.

As shown in the results for FY04, water-vapor radiometry can provide a significant improvement in performance of the EVLA. If the typical interferometer coherence at high frequencies were to improve from 80% to 90%, often achievable in average weather, this would be the equivalent of increasing the effective integration time by 20%, providing substantially greater science return. The Mission Requirement Level budget includes funding for Phase I as well as for the hardware in Phase II. The personnel needed for Phase II are not all available in the Mission Requirement Level budget for FY05 and FY06, so they have been stretched out into FY07. The cost of Phase III, the full implementation on the VLA, would require additional budget and would return an EVLA with significantly enhanced science capability.

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VLA + Pie Town Link

The VLA+Pie Town real-time link over a fiber-optic connection will be offered from September 2004 through January 2005, while the VLA is in the A configuration. The Pie Town link doubles the effective resolution of the VLA in one or both sky dimensions, depending on the declination of the source and the length of the observation. This A configuration cycle in fall/winter of FY05 is of particular interest because it combines the increased resolution of the Pie Town link with good winter phase stability for the newly completed low-noise systems at 22 and 43 GHz. Thirty proposals requested 522 hours of Pie Town link observing at the June 1, 2004 proposal deadline. Nineteen proposals had at least some time allocated using the Pie Town link, for a total of about 250 hours of observing. The next A configuration after the upcoming one will be January - April 2006; a decision on offering the VLA+Pie Town link for that time will depend on the requirements of the EVLA project and the scientific value of using the link during the good winter weather.

Long-Wavelength Astronomy

We are discussing with the Southwest Consortium for Long-Wave Astronomy the possibility of hosting a prototype 74-MHz antenna “patch” on the VLA site and connecting it to the VLA in FY05. This would be a prototype for a future array of low-frequency antennas that is a descendant of the former LOFAR project. The Long Wavelength Array (LWA) would provide an additional capability for the centimeter- decimeter radio astronomy center, would provide an opportunity for a university community to develop and build an important radio telescope, and also could provide significant infrastructure that could be used later by the New Mexico Array. LWA activities at the VLA will be funded externally and managed so that they provide the aforementioned benefits without causing delays on the EVLA project or compromising VLA/VLBA operations.

Infrastructure

The implementation of the EVLA project relies on existing infrastructure at the VLA. Design of the EVLA is aimed at performance through the year 2030 or so. But at that time the VLA site, much of the infrastructure, the antennas, and the unique antenna transporters all will be 50 years old or more. The need to maintain the facility over this much-longer term, as one of the key elements that will enable us to realize the scientific capability of the EVLA, means that vigilant attention must be paid to the maintenance and ongoing replacement of aging infrastructure and equipment. During FY05, we will conduct an assessment of possible long-term infrastructure requirements in addition to those previously identified and mentioned below, in order to anticipate future activities that may be needed in order to keep the VLA robust through 2030. Examples of items that will be assessed include the focus/rotation system on the VLA antennas, the elevation bearings, and the VLA site buildings.

An ongoing program of inspection of the antennas and the bearing grease has identified four antennas currently in need of bearing replacements (eight VLA antennas already have undergone replacements of their azimuth bearings); we expect additional antennas to require bearing replacements in the future. At the end of FY03 four new azimuth bearings were purchased for VLA antennas, in addition to one that had been purchased earlier during the year. These new bearings cost $45K each, while refurbished bearings cost $25K each. A goal of the increased cadence of bearing replacements is to “get ahead” of the worst bearing deterioration. This will enable old bearings to be removed while they still are in good-enough condition to be refurbished, thus saving $20K per bearing. In FY05 the azimuth bearings on VLA antennas 16 and 18 are scheduled to be replaced as part of this increased program.

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Approximately 3500 rail ties will be replaced on the VLA rail system in FY05, using our existing supplies from FY04 as well as about 2500 more ties (and accompanying ballast) that will be bought in FY05. Figure 6.11 shows some of the work being done to replace a bad section of rail; in the foreground is the machine that tamps down the track ties. Note the extensive supply of ballast (i.e., small sharp- edged rocks) that is required to support the ties. Instead of hiring additional personnel to work on the rail system, we have allocated $90K of funding at the end of FY04 to purchase a “rail car mover” and two ballast cars to haul rail ballast to work sites efficiently. These vehicles will begin operation in FY05, which will enable the “retirement” of three or four of the six ancient dump trucks presently in use at the VLA site and will reduce the use of rough dirt roads along the array arms. These roads are not formally maintained, but kept open by use only. In turn, we then can reduce the number of NRAO personnel who must maintain Commercial Driver’s Licenses to operate the dump trucks costs in the auto shop at the VLA. Maintaining the desired long-term average replacement rate of 5000 ties per year requires an expenditure of $300K per year for materials (each tie costs $30 and requires a ton of ballast costing another $30).

Figure 6.11. Track crew in operation replacing a bad section of track on the railway used to transport VLA antennas. The machine in the foreground is a track “tamper,” which is used to secure in place the ties that support one of the sections of the double (two-track) railway. This railway must support 320 tons of transporter plus antenna during reconfiguration.

VLA Operations and the EVLA are sharing the cost of erection of a new storage warehouse at the VLA site. This will be used initially for storage of EVLA materials that must be purchased in large quantity to get the best possible prices. After the EVLA project is completed, this warehouse will provide additional work space for the local VLA maintenance personnel. The new warehouse is expected to be completed early in FY05.

The cryogenic systems on the VLA antennas currently use R-22 refrigerant, an HCFC hydrochlorofluorocarbon) refrigerant whose production is being phased out (under the Montreal protocol) to protect Earth’s ozone layer. We would like to recover the R-22 refrigerant in an environmentally friendly way and retrofit the cryogenic systems to use R-410A, an HFC (hydrofluorocarbon) refrigerant

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that contains no chlorine and apparently has little capacity to damage the ozone. The total retrofit cost of $40K is on our list of tentative purchases to be made out of contingency in the FY05 budget.

During FY05, we plan to continue a practice (begun in FY04) of holding at least $100K in contingency funding out of the nominal operations budget for Materials and Services. This unallocated contingency will be kept available for unexpected costs such as failed elevation bearings on VLBA antennas. In FY04 the contingency was not needed for emergency expenditures, so it was allocated late in the year to the purchase of rail vehicles that will be used to transport ballast to sites of track maintenance work, as well as for 1000 additional railroad ties.

Several looming infrastructure costs are not funded in the current Mission Requirement Level budget. The fleet of rail vehicles at the VLA is getting quite old, and “new” vehicles are found only on government surplus lists, from other agencies that are getting rid of them. We have constructed a sustainable vehicle plan that would require spending $100K per year to maintain a steady state. In FY03 we completed a long-term effort to repaint all the VLA antennas; after a break of several years, we anticipate having to restart that project in FY06 or FY07. Finally, the EVLA is expected to use considerably more power than the VLA, both in the antennas and in power consumption by the correlator. This will lead to increased electricity costs as well as the possible need for a third diesel generator to supply sufficient power to run the VLA when the power grid is not reliable. The total cost is unclear because the power consumption estimates for the correlator and new antenna equipment still are uncertain. All these long-term infrastructure costs are not included in the current Mission Requirement Level budget.

Cost Summary for Desired VLA Enhancements

This section provides a cost summary for key VLA infrastructure enhancements and new capabilities that are not part of the EVLA project. Routine, ongoing maintenance and operations costs are not incorporated. In FY05 the Mission Requirement Level budget will be required to resume the routine purchases of ties and ballast, since the supplies bought using an FY01 infrastructure augmentation now have been exhausted. The first two phases of the water-vapor radiometry project would continue, though Phase II would begin to stretch out relative to the ideal plan. The beginning of Phase III is carried as an “over-budget” item in FY07.

In future years, we would buy a supply of ties and ballast that is about 2/3 of the recommended amount for the VLA, in order to maintain some progress on water-vapor radiometry and to begin 43 GHz holography. In FY06 and FY07, a difficult choice may be faced between continuing the water-vapor radiometry project (important for optimal EVLA science) and enhancing the VLA infrastructure, specifically the railroad, cryogenic systems, and azimuth bearings. The table below provides a summary of a sample funding profile for FY05 through FY07; all costs are in FY04 dollars. Note that the “Items funded” in FY05 fall about $100K below FY06 and FY07; this is because we anticipate spending some operations funds on Mark 5 recording systems for the VLBA in FY05 (see the VLBA section).

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Table 6.4 High-Priority VLA Enhancements, FY05-FY07 FY05 FY06 FY07 Items funded in Mission Requirement Level budget: Ties and ballast $200K $200K $200K Reconditioned azimuth bearings $0K $50K $50K Water vapor radiometry, Phase I prototype $30K $0K $0K Water vapor radiometry, Phase II $72K $90K $70K 43 GHz holography $0K $50K $50K

Items unfunded in Mission Requirement Level budget: Student support program $150K $250K $250K Refrigerant replacement for cryo systems $40K $0K $0K Replacement of aged rail vehicles $100K $100K $100K Additional ties and ballast $100K $100K $100K Water vapor radiometry, Phase III $0K $0K $280K

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Very Long Baseline Array

VLBA Operational Status

The VLBA is an instrument devoted to Very Long Baseline Interferometry (VLBI), with ten antennas distributed throughout the United States in a configuration that optimizes the distribution of baseline lengths and orientations. It is the only such dedicated VLBI instrument in the world. The VLBA has baselines between 200 and 9000 km, which provide angular resolution as fine as 0.1 milliarcseconds at 86 GHz. The shorter baselines, and hence the highest concentration of antennas, are near the VLA for optimal joint observations. The antennas are 25 meters in diameter and of an advanced design which allows good performance at 43 GHz and useful performance at 86 GHz. Table 6.5 summarizes the performance of the instrument at its ten frequency bands. The antennas are operated remotely from the Socorro Array Operations Center; local intervention is required only for recording media changes, routine maintenance, and troubleshooting. The current recording rate is limited to an average of 128 Mbps (Megabits per second) which fills two tapes every 24 hours. New disk-based recorders are being installed that should eventually permit recording rates up to 1024 Mbps with media changes once every 24 hours or longer.

The VLBA correlator is located at the Array Operations center (AOC) and is able to correlate as many as eight input data channels from each of 20 antennas simultaneously. For most modes, the correlator can provide 1,024 spectral points per baseband channel, and up to a maximum of 2,048 spectral channels per station or baseline can be provided for each recorded signal. In order to join long VLBA baselines with the shorter baselines of the VLA and perform high-sensitivity imaging over a wide range of scales, increased bandwidth is critical for the VLBA. This will require a substantially increased capability for VLBA correlation, which can probably be done most cost-effectively by an expansion of the EVLA correlator hardware now under development.

Table 6.5 VLBA Receiving Systems Frequency Range Typical Zenith SEFD1 Typical Zenith Gain (GHz) (Jy) (K Jy-1) 0.312 to 0.342 2217 0.097 0.596 to 0.626 2218 0.090 1.35 to 1.75 295 0.093 2.15 to 2.35 325 0.094 2.15 to 2.352 344 0.089 4.60 to 5.1 289 0.132 8.0 to 8.8 299 0.118 8.0 to 8.82 391 0.111 12.0 to 15.4 543 0.112 21.7 to 24.1 976 0.104 41.0 to 45.0 1526 0.078 80.0 to 96.03 3500 0.030 1 System Equivalent Flux Density: The source flux density which doubles the system temperature. 2 With dichroic. 3 All except Brewster and St. Croix installed. Two antennas only cover the frequency range up to 90 GHz.

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Accomplishments in FY2004

Observing and User Programs

For several years the amount of scientific observing time used on the VLBA has remained fairly stable at about 55% of the number of hours in a year. In the first 10 months of FY04 the VLBA performed astronomical observing for 50% of the time. The decrease is largely due to the tape-limited data transfer to the correlator combined with an increasing demand for higher-sensitivity observations. These higher- sensitivity observations require an increased data rate which is larger than the current tape technology can support for observing stations that are regularly staffed only on weekday daytime shifts. Since increasing the data rate at the expense of actual time spent observing enhances the science rather than degrading it, we have changed our reporting numbers to reflect effective hours of observing at the sustainable data rate of 128 Mbps. Using the revised metric of 128 Mbps-hours, the VLBA observed for 60% of the available hours in the year.

The observations for a large VLBA proposal recommended by the Large Proposal Review Committee began late in FY2004; this program is the continuation of a previous large proposal. It involves long-term monitoring of the structures of more than 100 active galaxies at 15 GHz in order to determine the statistics of their structural changes and apparent superluminal motions. The program will span FY2005 and end early in FY 2006 after accumulating a total of 3 million seconds of observing time over the past several years.

A continuation of the effort to make the VLBA easier to use has resulted in easier calibration for the VLA when used as a part of a VLBI array. Calibration data from the VLA, either as a phased array element or a single antenna, now is attached to the correlated data. Therefore, for the most part, VLBI calibration of the VLA can now be treated much more like that of a VLBA antenna with less effort on the part of the user.

Mark 5 Recording System

VLBI observatories around the world are moving rapidly away from tape-based and towards disk-based recording systems (Mark 5). Disk-based recording has many advantages over traditional tape-based systems, including lower error rates, greater bandwidth, increased capacity, and improved maintenance. The cost of a single Mark 5 recording unit, at $16K-$18K, is an order of magnitude less than the cost of a tape-based VLBA recording unit. The cost of the media, while cheaper than tape, is still significant, currently at 85 cents per Gigabyte for a recording module containing eight 250-Gbyte disks. (We have high confidence in these costs, since purchases at the specified prices already have been made.) To go to a sustainable bandwidth of 512 Mbps would cost more than a million dollars extra but could be reduced by phasing in the implementation over several years, as disk prices (presumably) continue to fall. (See the FY05 section for more details.)

The first successful Mark 5 demonstration on the VLBA took place in early FY04 using the Mark 5 disk- based recording system on Pie Town (PT). Figure 6.12 shows a new Mark 5A unit at the VLBA correlator next to one of the tape drives currently used for data recording and playback. A Mark 5A recorder has been installed at PT and we used PT with disk recording for an increased fraction of the time near the end of FY04. Funding to begin the Mark 5 conversion has been generated by reducing maintenance on the tape drives, particularly by stopping purchases of expensive parts such as headstacks and capstan motors, as well as by cutting our VLBA operational staff by two people and reorganizing the

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supervision in VLBA Operations. As tape drives are decommissioned on the correlator or at the stations, headstacks and capstan motors are stripped off and saved as replacements, so that no more purchases of such devices are necessary.

In addition to PT, sufficient funding was used in FY04 to convert Kitt Peak (KP) and Los Alamos (LA) completely from tape to disk recording. This is expected to take place in the first few months of FY05, after sufficient operational experience has been obtained at PT. The complete conversion for the entire VLBA includes implementation of a Mark 5A system at the station, an accompanying playback drive at the correlator, and sufficient disk media (at least 40-50 Terabytes per station) to support observing at 128 Mbps for five weeks. In June and July 2004 we ordered a total of 60 disk modules with a total capacity of 120 TB, which should be barely adequate to support full-time 128 Mbps recording at PT, LA, and KP at the beginning of FY05. The Mark 5A systems we have are capable of recording at rates up to 512 Mbps, but this would be feasible on a routine basis only with a larger supply of higher capacity disks. We are working with Haystack Observatory to define a Mark 5B unit that would provide 1 Gbps recording capacity at the VLBA.

Figure 6.12. A new Mark 5A playback unit (right), including a module with 2 TB of disk, is shown at the VLBA correlator. By comparison, the much larger tape drive at the left has a capacity of only 0.6 TB on a 35-cm tape reel.

Spacecraft Navigation

The VLBA Spacecraft Navigation Pilot Project formally began early in FY04 after informal tests (reported on in last year’s Program Plan) had been carried out during FY03. The Project, funded by NASA, is studying several aspects of VLBA phase-referencing measurements as a vital adjunct to conventional spacecraft navigation. The importance of this effort may increase in support of NASA’s new Exploration Initiative. The central task is being carried out in collaboration with several groups at the Jet Propulsion Laboratory to assess the feasibility of this approach. Several observations of the Stardust, MER-A, and MER-B spacecraft have been taken and analyzed. When complete, this study will include an evaluation of the precision achievable via phase-referenced VLBA observations of spacecraft downlink transmitters and the enhancement of navigation results produced by the inclusion of such

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measurements in the overall solution. In addition, the NRAO is developing designs and cost estimates for upgrading VLBA hardware, software, and operational procedures in several areas (e.g., correlator, Mark 5 playback interface, new 33-GHz receivers). Eventually, these all would be required to support routine spacecraft-navigation observations with adequate sensitivity at NASA's new space-communication frequency band.

We look forward to a successful conclusion of the pilot project at the end of FY04. Some additional funding and time may be necessary to complete a wide range of spacecraft tests, since such tests were slowed in FY04 by the necessity to convert the VLBA correlator relativity model to account for radio targets present within the solar system, rather than the traditional VLBI targets that are far beyond the Sun’s gravitational influence.

High-Frequency Systems

The major new frequency capability being developed for the VLBA over the last several years has been the addition of 80-96 GHz receivers to most of the antennas. This has been funded partly out of the NRAO operating budget and partly by the Max Planck Institut für Radioastronomie (MPIfR). Presently, only eight antennas are equipped; the wet weather at St. Croix (SC) and the poor subreflector at Brewster (BR) mean that it is not worth spending the money to equip either antenna at present, although steps to correct the BR station are under way (see below).

The performance of the VLBA antennas at high frequencies (86 GHz) is limited by the surface accuracy of the primary reflectors and subreflectors. During 2001 the NRAO began an effort on a local holographic system to improve the VLBA antenna surfaces with the goal of increasing the 86 GHz aperture efficiency to 25-30%. Substantial progress in this area would require the allocation of approximately 2-2.5 person- years per year, as was possible for the VLA 43 GHz systems from the mid-1990s, through approximately 2002. However, budget limitations have precluded this type of effort; instead, we have attempted to improve the 86 GHz aperture efficiency as a research project, using roughly 15% of the time of a scientist, 5% of the time of two engineers, and 10% of an antenna mechanic. For this reason, progress has been slower than desirable over the past several years. Early in FY04, a spare subreflector was resurfaced using a high-precision measuring machine and installed at PT. We have seen some improvement in the antenna's performance at 86 GHz, but not at the level expected from the 155 micrometer rms measured on the resurfaced subreflector. The primary surface is waiting for panel adjustments late in FY04.

The surface error of the BR subreflector was known to be larger than those of the other VLBA antennas. The BR subreflector was replaced with the reconditioned subreflector from PT during a maintenance visit in August 2004, as illustrated in Figure 6.13. Tests conducted at 43 GHz have confirmed a significant improvement in aperture efficiency at BR, from 30% to almost 50%. Many of the parts for a ninth 86 GHz receiver are in hand, and it is the subreflector replacement now makes it worthwhile to assemble and deploy the ninth 86 GHz receiver at BR. Installation of a 10th 86 GHz receiver at SC is not planned, because of the generally poor weather and extremely high precipitable water-vapor content of the atmosphere above this Virgin Islands station.

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Figure 6.13. The re-worked subreflector from Pie Town being installed on the Brewster VLBA antenna in August 2004.

Infrastructure

During FY04 tiger-team maintenance visits were made to three VLBA antennas; PT, BR, and Fort Davis (FD). In addition to conducting routine maintenance procedures, the team installed fall-arrest systems on the antennas, installed new power supplies for the antenna control units, and replaced analog tachometers with digital tachometers. The installation of the fall-arrest system at FD completes a program that was begun in FY03.

The old analog tachometers on the VLBA antennas have long been expensive high-maintenance items, so a program was started in the first quarter of FY04 to replace the analog tachometers with low-noise digital tachometers. By the end of FY04, the new digital tachometers were installed on the three antennas receiving tiger-team visits, plus a fourth antenna at Hancock, New Hampshire (HN).

The grout that distributes the weight of the antenna from the azimuth rail to the concrete foundation is deteriorating at the VLBA stations in PT and Mauna Kea (MK). The grout at these two stations was repaired in FY04.

In response to inquiries from our hosts at two VLBA sites, a preliminary study was made of the cost of relocating a VLBA antenna to another site. This cost would be roughly $5M on the continental U.S. No future action is planned in this area unless the inquiries become more forceful.

Plans for FY2005

Mapping the Future of VLBI Science in the U.S.

In FY04 the NRAO and Haystack Observatory were co-leaders of a community-wide effort to develop a science case and roadmap for U.S. VLBI over the next five years. The findings of this committee were presented in their report, “Mapping the Future of VLBI Science in the U.S.” Key recommendations for

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technical improvements are (1) the implementation of disk-based (Mark 5) recording systems; (2) significant enhancement to the sensitivity of VLBI arrays; (3) improvement of the high-frequency VLBI capabilities available to users; (4) software enhancements to make data easier to acquire, calibrate, image, and analyze; and (5) community enhancements through funding for observers and making VLBI an easier technique for non-experts. Most of the plans for FY05, described below, are responsive to this report.

The VLBI enhancements recommended in the above-mentioned report are being assessed, and a full project plan is being developed for the implementation of the first two recommended phases over the next five years. A portion of the recommended improvements are carried in Table 6.6, at the end of this section, together with preliminary cost estimates; a full cost estimate will be provided as part of the VLBA-2010 project plan to be completed in FY05. Implementation of the bulk of the recommendations is highly desirable in order to bring the VLBA to forefront status, commensurate with that of the EVLA, and into its place as a key component of the center for centimeter/decimeter interferometry that is naturally headquartered in NRAO-New Mexico. The first two phases, to be carried out over five years, would bring the VLBA to a total data rate of 4 Gbps, and a bandwidth of 500 MHz at each of two polarizations, still well below the 96 Gbps and 16 GHz dual-polarization bandwidth of the EVLA. Higher sustainable data rates and bandwidths may well require “eVLBI” (electronic VLBI). In this system, data would be transmitted to the correlator in real time over fiber links rather than via intermediate recording media. The availability of eVLBI will depend on commercial and infrastructure developments in wide-band communications over the next few years.

Mark 5 Recording System

Using operations funds saved from tape maintenance and personnel expenses saved by performing the NASA pilot project, we bought sufficient materials to enable us to convert PT, LA, and KP to disk-only operations during the first quarter of FY05. In a joint venture in support of the Huygens probe descent into the atmosphere of Titan, NASA and ESA have agreed to purchase six Mark 5A recorders for deployment on the VLBA and the GBT. This will bring our total number of recorders to 13 out of the 35 eventually needed for all VLBA stations, the VLA, the GBT, playback of “foreign” stations at the correlator, and spares. The minimal full implementation of Mark 5A thus would require an additional 22 Mark 5A recorders and approximately 350 Terabytes of disks, assuming that non-NRAO stations sending data to the correlator use their own disks. Assuming costs equal to those discussed for Mark 5 systems in the "Accomplishments in FY2004" section, the additional funding required in FY2005 would be $665K, perhaps somewhat less if disk prices drop. To realize an increase in the sustainable recorded bandwidth up to 512 Mbps, doubling the average sensitivity of the VLBA, an additional 1400 TB of disk media would be needed at a cost of $1.2M (assuming FY04 prices). To reach 1 Gbps recording we will need to upgrade our Mark 5A recorders to the Mark 5B recorders currently under design at Haystack; these systems now are not expected to be on the market until FY06.

Spacecraft Navigation

With the successful conclusion of the pilot project at the end of FY04 and the demonstration that the VLBA can provide accurate absolute positions of spacecraft in a format usable by NASA for navigational purposes, we plan to negotiate a mutually beneficial and regular spacecraft-navigation project with NASA. This project will include observing various satellites for some small number of hours each month, yet to be decided, as well as a regular program of monthly observations to build up a 33 GHz astrometric catalog. As part of this program, the conversion to disk-based recording at 128 Mbps would be funded in part by NASA. The consequent increase in astronomical observing efficiency would more

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than compensate for the 300-400 hours/yr spent observing satellites and constructing the new catalog. An additional requirement for the spacecraft tracking and catalog development would be installation of 33 GHz receivers on the VLBA over the FY05 and FY06 period. These receivers would be paid for by NASA in exchange for the spacecraft support and also would be the lowest-noise high-frequency receiving systems for astronomical observations using the VLBA. A full cost estimate for the new 33 GHz systems is under development.

A key requirement for NASA spacecraft navigation is rapid data turnaround, much more rapid than is feasible by shipping of recording media from observing stations to the VLBA correlator. If the operational spacecraft navigation project moves forward in FY05, we anticipate that we will be able to make a more serious assessment of operational eVLBI in the U.S., and the possible route to implementation on the VLBA.

The High-Sensitivity Array (HSA) and Global VLBI

Proposals for a VLBI High-Sensitivity Array (HSA) consisting of the VLBA, Green Bank Telescope (GBT), phased VLA (Y27), Effelsberg (EB), and Arecibo (AR) were accepted at the June 1, 2004 deadline, with first observations scheduled for early in FY05. A total of up to 100 hours in each trimester (~25 hours/month) may be scheduled for highly rated projects that can justify the increase in sensitivity; 74 hours of observing were accepted at the first proposal opportunity. By adding the large telescopes to a VLBA experiment, the sensitivity can be increased by more than an order of magnitude. A plot of the sensitivities available in 1 hour at frequencies ranging from 1.6 to 43 GHz is shown in Figure 6.14. Clearly, the HSA capability opens up promising new avenues for scientific discovery (e.g., studies of low-power active galaxies, extragalactic masers, and gravitational lenses). The aim of the High Sensitivity Array initiative is to facilitate the planning, scheduling, and calibration of observations making use of this array. At the June 2004 deadline, fully a third of the VLBA proposals requested HSA, indicating a strong demand for this capability, and 74 hours of observing time were allocated. Improvements to the transfer of calibration files from the GBT and Arecibo will continue in FY05 in order to further streamline the calibration of VLBI experiments using the HSA.

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Figure 6.14. Plot of the rms noise vs. observing frequency for a VLBI observation with 1 hour on source at a data recording rate of 256 Mbps. Both the stand-alone VLBA and the High Sensitivity Array are plotted. The significant noise increase for the HSA above 10 GHz is due to the inability of Arecibo to operate at the higher frequencies.

The VLBA will continue to participate in the Global VLBI observing sessions that are carried out three times per year. By using antennas in the U.S. and Europe together, the opportunity arises for increased sensitivity and twice the resolution that could be achieved with either the U.S. or Europe alone. Proposals for Global VLBI observations are submitted separately to NRAO and to the European VLBI Network (EVN), refereed separately by the VLBA and EVN referees, with time allocated by joint decision of the VLBA and EVN program committees. During FY2005 the three Global VLBI sessions will take place in October/November 2004, February/March 2005, and June 2005. In addition to the standard Global VLBI, a new international network that observes at 86 GHz will enter its second year in FY05 with two sessions of 5-7 days each. This array includes the VLBA, Pico Veleta, Effelsberg, IRAM, Onsala, and Metsahovi, facilitating the highest angular resolution (better than 100 microarcseconds) currently achievable using VLBI techniques.

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High-Frequency Systems

As of March 2004, there were eight VLBA antennas equipped at 86 GHz: LA, PT, KP, OV, FD, NL, MK, and HN. Most antennas have receiver temperatures in the range 50-70 K, typical system temperatures at zenith of 120 K, and low passband ripple. Four of these receivers were funded by the Max-Planck- Institut für Radioastronomie (MPIfR) in Bonn, Germany, while the remaining new and upgraded systems were made possible using NRAO operations funding. At NL and HN the system temperatures are significantly higher (200-300 K), and at HN the efficiency is quite poor (5%).

To improve the performance of the VLBA antennas at high frequencies, efforts have continued to develop the capabilities needed to measure and adjust both the main dish and the subreflector, as described in the FY04 section. Further improvements to the dish and subreflector surfaces for improved 86 GHz performance are highly desirable, and could be carried out with a budget augmentation of approximately $250K per year. Since such funding is not currently available within the operations budget, we have engaged in preliminary discussions with the MPIfR about a possible joint project to improve the 86 GHz performance. We will aim either to move the 86 GHz receiver from HN to BR or to assemble and deploy the ninth 86 GHz receiver at BR. Currently, we are carrying the ninth 86 GHz receiver as a primary use of the contingency funding in our FY05 budget; if unexpected expenditures do not arise, we anticipate completing this receiver late in the fiscal year.

Both the 22 and 43 GHz receiving systems at the VLBA stations are operating with fairly old low-noise amplifiers, and sensitivity improvements of order 50% could be realized by replacing the old amplifiers with current state-of-the-art devices. An immediate direct benefit would be an improvement in the VLBA ability to image extragalactic water-maser sources, which can be used both to measure central black-hole masses directly and to make geometric distance determinations to external galaxies. Upgrades of the 22 GHz and 43 GHz systems would cost about $250K each, including hardware and installation as well as scientific testing and integration.

Software and User Community

The primary software enhancements under development currently are within the AIPS group, for construction of autoflagging routines, development of more robust user pipelines, and operational implementation of those pipelines. Since the resources of the AIPS group are fully occupied for support of our current capabilities and current user community, any improvements are only carried out as research projects on a best-efforts basis.

The student grants program for the Green Bank Telescope has been the most notable success in bringing new radio astronomers into the community, and a similar program is envisioned for the VLBA. This program depends upon agreements with the affected universities that student research programs are supported under the grants, but tuition is not covered and only minimal overhead is charged. The estimated cost of this program for the VLBA is $150K in FY05 and $250K per year in the future. Such funding would be one of the requirements if we are to build the world’s centimeter/decimeter interferometry science center in NRAO-New Mexico.

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Infrastructure

The primary infrastructure activities planned for FY05 are the routine tiger-team maintenance visits that will be made to MK, HN, and LA. At these visits, the analog tachometers at MK and LA will be replaced with the new digital versions. In addition, digital tachometers will be installed at Owens Valley (OV). At the end of FY05 we expect to have the new tachometers installed at 7 out of 10 stations. Figure 6.15 shows one of the first installations, made at the PT station in FY04.

Figure 6.15. A new VLBA digital tachometer is shown installed on the drive motor of an azimuth wheel at the Pie Town VLBA station. For context, note the azimuth rail and the fence for the site enclosure in the upper background.

Cost Summary for Desired VLBA Enhancements

Below we give the cost summary for desired VLBA enhancements in FY05, FY06, and FY07, most of which respond to the “VLBI Future” report. A more detailed long-term project plan will be prepared in FY05, as a full response to that report. General maintenance items, such as the routine tiger-team maintenance visits and ongoing operations, are not specifically called out below. Only completion of the digital tachometers project and the HSA implementation are possible in FY05 within the Mission Requirement Level budget presented herein. Completion of Mark 5 implementation and the beginning of 33 GHz implementation may occur if negotiations for NASA funding are successful.

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Unfunded items are listed in the second half of the cost table in approximate priority order; most have been discussed in the text above. Should substantial additional funding become available, consultation with our user community would take place in order to determine the final ordering of the priorities. Enhancement of the sustainable data rate to 512 Mbps would require $1.2M worth of additional disk media at today’s cost of 85 cents per Gigabyte. Enhancement to 1024 Mbps would require approximately $144K to upgrade Mark 5A units to Mark 5B units (not possible until FY06) and roughly $1.7M in additional disk media at today’s prices. The table below anticipates a modest reduction of 10% per year in disk prices after FY05. Operation at 1024 Mbps may require use of the EVLA correlator for processing of VLBA data, because the required data rate is beyond the sustainable capacity of the current VLBA correlator. Funding for this use of the EVLA correlator was included in the EVLA Phase 2 proposal, so it is not called out separately here.

Table 6.6 High-Priority VLBA Enhancements, FY05-FY07

FY05 FY06 FY07 Items funded in Mission Requirement Level budget: Digital tachometers $15K $15K $0K HSA implementation (personnel costs) $40K $20K $20K Mark 5, 128 Mbps (NASA funding $665K $0K $0K anticipated for most) 33 GHz receivers (NASA funding ~$1000K ~$1000K $0K anticipated)

Items unfunded in Mission Requirement Level budget: 9th 86 GHz receiver $50K $0K $0K Student support program $150K $250K $250K Software enhancements for ease of use $200K $200K $100K Increase sustainable data rate from 128 $600K $540K $0K Mbps to 512 Mbps Increase sustainable data rate from 512 $0K $144K $1380K Mbps to 1024 Mbps 22 GHz noise reduction $250K $0K $0K 43 GHz noise reduction $0K $250K $0K Subreflector & primary surface $250K $250K $250K improvements (2.5 FTEs) eVLBI (electronic, real-time VLBI, started $0K TBD TBD by NASA?)

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Cooled HFET Development

The NRAO has worked on the development of HFET (heterostructure field-effect transistor) amplifiers for many years and is the recognized leader of cooled HFET amplifiers for radio astronomy use. The highest-frequency amplifiers cover the band 68-116 GHz with noise performance comparable to SIS mixers and much wider instantaneous bandwidth.

The NRAO has produced hundreds of advanced HFET amplifiers for use on NRAO telescopes and for others in the radio-astronomy community and other research areas. These range from low-frequency amplifiers (for <1 GHz) used in fundamental particle physics and magnetic-resonance imaging development to the highest attainable frequencies for cosmic microwave background experiments. At the lowest frequencies, special balanced amplifiers have been developed which largely eliminate the need for bulky isolators and have better immunity to the effects of interference.

Accomplishments

It is vital to the new EVLA receiver plan that we have new wideband amplifiers, particularly for the 1-2, 2-4, and 4-8 GHz bands, which can be used in receivers having the high dynamic range need to cope with the RFI levels found at the EVLA site. For the two lowest frequency bands, balanced amplifiers are necessary because wideband, low-loss cooled isolators are not possible at these frequencies. We successfully developed a single-stage balanced low-noise amplifier optimized for the 1.2-2.0 GHz band which is usable down to 1.0 GHz and built several production units for use in receiver prototyping. We also developed a second-stage amplifier with higher noise and a much higher power output than is possible with low-noise devices, providing the high dynamic range needed to cope with RFI. A paper design for a balanced amplifier for 2-4 GHz has been completed. The 4-8 GHz band, for which isolators are available, is covered by the 3-13 GHz amplifier already developed, albeit it with slightly less than optimum noise performance.

Figure 7.1. High-power (left) and low-noise (right) L-band amplifiers for the EVLA.

The unsurpassed performance of the higher-frequency amplifiers has been made possible by the use of the transistors developed under JPL leadership for its CHOP program, in particular the wafer run known as “Cryo3”. We came to an agreement with JPL to buy into the CHOP program and obtain access to the thousands of available devices for use in our amplifiers.

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There was further work in the area of support for cosmic microwave background experiments, as a follow-on to the WMAP amplifier development. Marian Pospieszalski joined the Planck satellite team at Jodrell Bank and helped with their amplifier development for the 40 GHz amplifier for Planck. He also contributed to the CalTech CBI experiment by upgrading their amplifiers with Cryo3 devices in order to improve sensitivity for the search for the polarization characteristics of the CMBR.

Production amplifiers were built for receiver systems on the GBT and VLA. The total number of amplifiers produced was 70. The following Table 7.1 lists current production amplifier models.

Table 7.1 Current NRAO Production Amplifiers Band(GHz) Name Noise(K) Comment 0.3-0.4 2.0 Balanced 0.4-0.5 2.0 Balanced 0.5-0.7 2.0 Balanced 0.7-0.9 3.0 Balanced 0.9-1.2 3.0 Balanced 1.2-1.7 L 3.0 1.0-2.0 L 4.0 Balanced, InP 1.7-2.6 L/S 4.5 2.6-4.0 S/C 5.2 3-13 S/C/X 2.5 InP 8-18 Ku 4 InP 18-26.5 K 7 InP 26.5-40 Ka 8 InP 36-50 Q 10 InP 65-90 V 45 InP 68-116 W 31-50 InP (3 variations)

Planned Activities

The development of a medium-noise, high-power-output amplifier for the second stage of the EVLA 1- 2 GHz receiver will be completed and several production units will be fabricated. This work involves refining the present design and experimenting with several different types of commercially available GaAs transistors in order to optimize performance.

The low-noise and medium-noise, high-power designs for 1-2 GHz, once their performance is thoroughly understood and modeled, will be used to refine designs for similar amplifiers for the 2-4 GHz frequency band. Prototypes will be built and tested, and several production units will be built for use in receiver prototyping.

If time permits, a design for an unbalanced amplifier for the 4-8 GHz range will be developed, based upon the 3-13 GHz design but optimized for 4-8 rather than 8-12 GHz. This may permit improving the noise temperature by about 1 K. Again if time permits, we will refine the designs of the 26.5-40 and 40- 50 GHz amplifiers in order to optimize overall receiver noise performance for precisely these bands. The present designs were optimized for the WMAP satellite, and slight improvements for the EVLA receivers are certainly possible.

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Amplifier construction will continue at a rate sufficient to keep up with the needs of the EVLA and GBT. We anticipate that, for frequencies below 12 GHz, it will be possible to outsource the amplifier assembly so that we do not have to add to the amplifier technician pool. However, we will continue to perform the cryogenic testing since this function is not available commercially. Construction of amplifiers for 12 GHz and above will likely continue as an in-house activity during FY2005, although we will investigate contractor assembly for the higher frequencies as a possible alternative, based on the experience gained at lower frequencies.

MMIC Development

NRAO engineers are working on the development of Monolithic Millimeter-Wave Integrated Circuits (MMICs) and Multi-Chip Modules (MCMs) for use in the current and next generation of centimeter and millimeter-wave radio astronomy receivers. Custom MMIC power amplifiers, for example, are used in the ALMA local oscillator (LO) system. MMICs provide highly repeatable performance in a more compact package than traditional millimeter-wave assemblies, and at lower cost in large quantities. This dramatically improves the tradeoff between cost and performance in array architectures.

As the cost of GaAs and InP wafer runs is quite high, we exploit opportunities to share a mask set with collaborators. While these wafer runs are necessary to complete receiver components for existing projects such as ALMA and the EVLA, they are also the perfect opportunity to prototype new experimental designs for future upgrades and applications.

Accomplishments

In FY2004, these new MMIC prototypes have included:

1. Low-noise amplifiers, power amplifiers, multipliers, and mixers that cover future ALMA LO frequencies (bands 1, 4, 8, and 10). 2. 40-60 GHz low-noise and medium power amplifiers that fill a gap in the frequency coverage of commercially available MMIC chips (see Figure 7.2). 3. Uncommon control circuits in the 26-40 and 40-60 GHz bands that are difficult to find commercially, such as discrete-level step attenuators and multi-pole switches. 4. A wideband cryogenic LNA and LO multiplier for the 11-34 GHz frequency band of the U.S. Square Kilometer Array (SKA) concept (see Figure 7.3).

Figure 7.2. MMIC 40-60 GHz medium power amplifier designed at the CDL. Fabricated by Raytheon using a 0.15 µm MHEMT process. Chip dimensions are 2.6 x 0.8 x 0.1 mm.

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Figure 7.3. MMIC 15-27 GHz LO tripler designed at the CDL for the Square Kilometer Array. Fabricated by United Monolithic Semiconductors using a GaAs Schottky Diode MMIC process. Chip dimensions are 2.0 x 0.73 x 0.1 mm.

We have also developed new techniques for integrating high-performance filters and other passives within compact MMIC-based modules.

Planned FY2005 Activities

Plans for future developments include:

1. W-band (75-110GHz) MMIC LNAs and compact front-end packaging for single-dish focal plane arrays. 2. Extremely wideband (decade or more) components for general use and millimeter-wave test instrumentation. 3. Further components for the SKA 11-34 GHz band such as a downconverter and front-end package.

Millimeter-Wave Receiver Development

Most of the effort in mm-wave receivers was performed for the 211-275 GHz ALMA band, and that work is reported in the ALMA section of this plan. However, there were two areas of technical development outside the ALMA effort: development of a new SIS mixer design for 385-500 GHz, based on the highly successful 211-275 GHz results, and development of a Hot Electron Bolometer (HEB) mixer for 600- 720 GHz.

Accomplishments

385-500 GHz SIS mixer - This is a joint R&D project between S.-K. Pan of the NRAO and Arthur Lichtenberger of the University of Virginia (UVa), and is supported mainly by an NSF grant to UVa. Design of most of the mixer circuit elements has been completed, including the suspended microstrip-to- coplanar waveguide transition, capacitively loaded coplanar waveguide, microstrip, the pair of microstrip short-circuit stubs, and the RF choke for the 7 micron SoI (Silicon on Insulator) substrate circuit. The final mixer circuit optimization is still in progress. The objective is to complete a new design for this

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band (which is also ALMA Band 8) which will provide wideband tunerless operation with noise (measured in photons) comparable to ALMA Band 6, and which can be manufactured by the highly repeatable processes available at the UVA foundry.

HEB mixers - This investigation of beamlead HEB Mixers is a Small Grant for Exploratory Research awarded to Eric Bryerton by the NSF under the Approaches to Combat Terrorism program aimed at eventual development of a practical technique for heterodyne biohazard detection at THz frequencies. Other applications include THz imaging and THz receivers for astronomy. This is a one-year grant to build, measure, and compare different types of HEB mixers in a 600-720 GHz receiver using existing NRAO equipment. Using a new beamlead HEB process developed at the University of Virginia, phonon- cooled NbN and diffusion-cooled Nb HEB mixers have been fabricated at the University of Virginia on both Si and quartz. The intent is to investigate the physics of these mixers initially in a frequency range in which measurements are comparatively easy. Cryogenic measurements of the phonon-cooled HEB mixer were made and showed the expected superconducting transition. With the help of an NSF Research Experiences for Undergraduates student, a cryostat was outfitted for 600-700 GHz receiver noise measurements. Figure 7.4 shows the HEB mixer block mounted to a bracket with an off-axis parabolic mirror. The REU student also developed the measurement software in LabView to measure the mixer quickly over a range of LO frequencies using the ALMA Band 9 LO. A diffusion-cooled HEB mixer was assembled for comparison in the same receiver.

IF and dc bias connector

Diagonal Horn

Off-axis parabolic mirror

Figure 7.4. 600-700 GHz HEB mixer block on bracket with off-axis parabolic mirror.

Planned Activities

385-500 GHz SIS mixer - The design of the new mixer using the 7 micron SoI (Silicon on Insulator) process will be completed and a wafer will be fabricated. A mixer block will be designed and the mixer performance will be evaluated.

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HEB mixer - Measurements of the 600-700 GHz mixers of both types will be carried to completion. Using the results, HEB mixers targeted at a center frequency of 1.3 THz will be designed and simulated.

Electromagnetics

Wider-band amplifiers and mixers require wider-band supporting elements. We have designed and tested several new components with the goal of having receiver performance limited only by the bandwidth of single-mode waveguide at high frequencies and by feed dimensions at the low-frequency end of the spectrum.

Accomplishments

A complete polarizer for 26.5-40 GHz (Ka-band) including phase shifter, transition, and orthomode transducer (OMT) was put into production. These components work well over the whole waveguide band and are in use for the new GBT Ka-band receiver. They will also be used for the EVLA.

A substantial amount of work was done on the design of feeds and supporting elements for the GBT and EVLA:

• A prototype 1-2 GHz feed for the EVLA was built and tested (see Figure 5.3 in the EVLA section). Its performance was as simulated, and it has been installed on the first EVLA antenna with excellent results. The sensitivity at low elevation angles is much improved over the old VLA design because of dramatically decreased spillover. • Prototypes of Ka-band feeds (26.5-40 GHz) were designed and fabricated for both the GBT and EVLA; they perform as simulated. A preliminary design for a Ka-band feed for the VLBA to support the possible NASA spacecraft tracking activity was completed. The different antenna optics for these telescopes require slightly different designs in each case, but the polarizers will all be the same. • Preliminary designs were completed for the EVLA 2-4, 4-8, and 8-12 GHz feeds and supporting elements. Prototyping was done for the 4-8 GHz band. • A preliminary design for dichroic optics allowing simultaneous 8 GHz and 32 GHz observations, a possible configuration for the possible NASA spacecraft tracking activity, showed that such a system can be made to work well over the spacecraft communication bands while providing sufficient bandwidth for continuum observations of astrometric calibration sources. The extra reflectors would be mechanically removed from the optical path for astronomical observations.

Planned Activities

Work will continue for the 2-4, 8-12, and 12-18 GHz feed and polarization-separation elements for the EVLA. We will complete the designs, fabricate and test prototypes, and prepare for volume production in order to meet the EVLA schedule for outfitting antennas with the new receivers. This work is complementary to the development of optimized HFET amplifiers and the incorporation of all these critical pieces into prototype and early production receivers.

If the possible NASA spacecraft-tracking activity is funded, then the work on the Ka-band feed and possibly the dichroic elements will be completed and prototypes will be built and tested.

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A design for a 1.30-1.45 GHz prime focus feed system for the GBT will be undertaken with the objective of providing slightly lower system temperature and an even cleaner beam (lower near-in sidelobes) than is possible with the present Gregorian optics for low-redshift neutral hydrogen observations.

EVLA antenna performance will be modeled and simulated in detail using a reflector code based on Aperture Integration and Uniform Geometric Theory of Diffraction to evaluate performance at various bands using measured feed patterns. This will provide a theoretical understanding of the EVLA optics to a greater depth than present approximations permit.

Budget

The activities described above assume the Mission Requirement Level budget. If we receive only the PRL budget, there will be the following consequences:

1. We will be unable to purchase and use the advance electromagnetic software needed for complete analysis of antenna and receiver optics. 2. We will be unable to replace the old Apple II computers used in our amplifier noise-measurement systems.

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Introduction

In mid-2003 the Division of Science and Academic Affairs (DSAA) was created at the NRAO. The purpose of this new division is to provide a more coherent framework for the scientific and academic activities of the Observatory and especially to facilitate interactions with the U.S. university astronomy community. Special emphasis is placed on the stimulation of scientific research throughout the NRAO sites.

A number of existing committees are coordinated by the DSAA, including the Observatory Science Council, a committee to advise the director of NRAO on scientific issues, and the Observatory Committee on Tenure and Appointments (OCTA).

The Division’s activities also include the coordination of NRAO-sponsored conferences and the planning of joint university-NRAO meetings, the coordination of external proposals originating from the NRAO scientific staff, and the introduction of NRAO-wide colloquia. The Division assists in the assignment of telescope time, helping to insure that NRAO facilities are used in the best possible way to advance science and astronomy.

The Research Staff of the NRAO

The research staff comprises scientists with experience in different aspects of astronomy and astrophysics, in computer sciences, and in electronic instrumentation. A fraction of the time of each of the research staff is spent on personal research. By maintaining an active research interest, the scientist keeps abreast of the developments in her or his field of specialty, and is better able to maintain contacts with the broader user community. A fraction of the scientists’ time is spent in direct support of Observatory programs. In addition a fraction of the time is devoted to service to the broader astronomical community, coordinating planning for new instrumentation, serving on review panels, and providing referee evaluations for publications and grant proposals. This division of effort is analogous to that of university faculty who devote time to research, teaching, university affairs, and external service.

The scientific programs which are planned by the staff for FY2005 are summarized in Appendix A. The members of the research staff are listed in Appendix B. The major fields of astronomical and astrophysical research are well represented; many of the staff have strong backgrounds in radio- astronomical techniques.

Science Support

The support needed by the Observatory spans a wide range of functions. A demanding task is the continuing commissioning of the GBT; a number of staff have and will remain active in tests of the high- frequency performance (e.g. 7mm) of the GBT. Operating telescopes require scientific support throughout their effective life-times. Each system needs continuing assessment of its performance, and scientific involvement is important as upgrades are designed, developed, and implemented.

The scientific staff also provides assistance to visiting observers, since the latter frequently have experience at other wavelengths and need an introduction to radio-astronomy instrumentation. One component of this endeavor is assistance to visiting observers in the planning of new observations and in the analysis of the telescope data. In addition, the NRAO conducts orientation workshops in

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interferometry and, with the Arecibo Observatory, in “single-dish” radio techniques. In each case the scientific staff serve as the faculty of the school. In the summer of 2003 the single-dish summer school was held in Green Bank, and the interferometry summer school was held in Socorro in June 2004.

New Initiatives

A major role of the scientific staff is to help define and to implement new instrumentation and new facilities for radio astronomy. These activities include initiatives generated internally within NRAO as well as projects developed externally or jointly between NRAO staff members and the wider national and international community. During the next year and beyond, the scientific staff will continue to be involved in the ALMA and EVLA construction projects as well as planning for their operational phase, in particular to define the role of the North American ALMA Science Center (NAASC).

A number of NRAO scientific staff members are actively involved in the planning at the national and especially international level for the Square Kilometre Array with leadership roles in both defining the scientific goals as well as addressing the formidable technical and organizational challenges for this planned large international facility. Members of the scientific staff are also working with colleagues in the newly formed Southwest Consortium and the University of New Mexico to facilitate their development of a Long Wavelength Array (LWA) and the coordination of the LWA with NRAO activities in New Mexico. Planning for FASR, the Frequency Agile Solar Radio telescope, continues as a joint effort of NRAO and university scientists. Discussions between NRAO scientists and Japanese and Russian scientists to implement space VLBI facilities are ongoing. Smaller scientific staff programs to develop Focal Plane Arrays and research on RFI Mitigation will also continue in close collaboration with similar activities at other institutions.

Maintaining Association with the Scientific Community

The NRAO staff serve as a conduit by which the scientific community can maintain its connection to the NRAO. Staff personnel serve on advisory committees and review panels, serve as editors for professional journals, give colloquia and invited talks, and attend meetings and workshops on a variety of topics. In these activities there is an opportunity for the external scientists to discuss with their NRAO colleagues the state of current instrumentation, the direction of current research, and the need for new techniques and instrumentation.

Library and Archives

Library

The primary mission of the NRAO Library is to provide research support for the explorations of scientists, engineers, and students, to support the information needs of all NRAO staff, and, as the library of a national facility, to serve the wider astronomical community. This support is provided through collection development and document delivery. Collection development consists of identifying, purchasing and processing appropriate materials in a range of formats including paper, electronic, CDs, videos, DVDs, sky-survey plates, and observatory and institute publications from around the world. Ordering, billing, license negotiating, and cataloging of materials are library activities; core items may be duplicated in several locations for immediate access by NRAO staff. Document delivery networks have been formed with other libraries to provide materials not in the NRAO holdings. The NRAO Library also

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supplies materials to other libraries under national and international interlibrary lending agreements. The Library manages NRAO's staff and visitor page-charge support program.

The NRAO Library has collections and staff at several sites: Charlottesville (engineering at the NTC and all other materials at Edgemont Road), Green Bank, and Socorro. The Observatory Librarian left NRAO in early July 2004, and the search for a replacement to manage the Library system will begin in fall 2004. The new hire should be in place in Charlottesville by late 2004 or early 2005.

The Edgemont Road building in Charlottesville is being renovated and expanded with completion expected in late 2004. The expansion of the library is a major component of this project. Library services have been substantially disrupted in 2004 by the construction activities. In 2005, the new space will be occupied and 3 new offices for library personnel will be available. Both the shelf space and the reading- room space in the Library will be increased significantly.

The Library’s large collection of publications from other observatories and institutes is being processed and added to the online catalog. This project is about 50 percent complete and will continue into FY2005.

The Tucson facility will be phased out in the course of 2005. During late 2004 and early 2005, library staff will undertake an inventory of the Tucson library collection which will form the basis for developing plans for the disposition of the library materials in 2005. Tucson holdings will be compared to NTC and other NRAO collections to identify unique items for redistribution. Dispersion of Tucson library materials will be phased to parallel the relocation of ALMA staff to Charlottesville and Socorro.

NRAO Archives

The intent of the NRAO Archives is to actively seek out, collect, organize, and preserve institutional records and personal papers of enduring value which document NRAO’s historical development, institutional history, instrument construction, and ongoing activities, including its participation in multi- institutional collaborations. As the national facility for radio astronomy, it also is appropriate for the NRAO Archives to include materials on the history and development of radio astronomy in the United States, particularly if such materials are in danger of being lost or discarded by other institutions or individuals.

During 2004, planning was completed for the dedicated Archives space in the Edgemont Rd. addition, the Web pages chronicling Nan Dieter Conklin’s career as the first woman in U.S. radio astronomy were completed, the portion of Grote Reber’s correspondence currently at NRAO was indexed, approximately half of the correspondence and papers of John Findlay were indexed, and an inventory of the Findlay and Director’s Office files in the Edgemont Road attic was completed as a preparation for moving those files to the new Archives space.

The Archives has been in a small temporary office pending the completion of the Edgemont Road addition. The move into the new space in late 2004 will allow us in 2005 to begin gathering materials currently housed elsewhere in Charlottesville and at other sites. We will receive from Reber’s estate the significant portion of his correspondence and papers that he had retained in Tasmania, and in 2005 work will continue on processing both that material and the material still housed in Green Bank. Work will also continue on processing the Findlay material. A Web page presenting Doc Ewen’s informal recollections of events in U.S. radio-astronomy history is in process. We will begin putting data into Web-based

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finding aids that will allow researchers, both within and outside NRAO, to search indexes to the processed portions of the Archives collection. Once we have moved into our permanent space, we will be considering options for additional personnel to help with processing materials: grant support for specific projects, NRAO’s summer-student program, interns, and volunteers. The Archives will be actively involved in planning exhibits for the NRAO’s 50th anniversary in 2006.

Educational Programs

Undergraduate Research Program

The summer of 2005 will be the forty-fifth year of the NRAO Summer Student program. This program allows approximately 30 undergraduate and graduate students to spend a period of 10-12 weeks each summer at one of the three NRAO sites in New Mexico, West Virginia, and Virginia. The students are supervised by an NRAO staff member on a research project in the supervisor’s area of expertise. The project may involve any aspect of astronomy, including original research, instrumentation, telescope design and engineering, or astronomical software development. In addition to their research project, students take part in a summer lecture series, field trips to other astronomical observatory sites, and collaborate together on an observing project using one of the NRAO's radio telescopes. The students contribute materially to the research they are assigned, and these contributions are often reflected in co- authorship on resulting papers. At the end of the summer, students give oral presentations to the local NRAO staff and submit written reports. A majority of the students receive financial support from the NRAO to attend the American Astronomical Society winter meeting to present posters on their research projects.

In the summer of 2005, approximately 15 undergraduate astronomy students will be supported via the NSF-funded Research Experiences for Undergraduates (REU) program, with an additional 15 REU- ineligible students (graduating seniors, graduate and foreign students) funded out of the NRAO operations.

The NRAO has also established a co-op program wherein undergraduate engineering students from participating institutions work at one of the NRAO sites for two (non-consecutive) semesters. The program allows students to acquire important technical skills by working under the supervision of the NRAO technical staff on problems at the technological forefront. The program is presently funded through the NSF Cooperative Agreement.

Graduate Education

Professional astrophysics is a multi-wavelength problem-oriented discipline. Students entering the field need a wider range of skills than most college courses provide. To rectify this situation, and to train students in the techniques of radio astronomy specifically required for the individual student’s research, two programs are available at the NRAO. First, summer-student positions for graduating seniors and first- and second-year graduate students are available (as described above). They allow students to gain experience in radio astronomical research early in their graduate careers, and to establish important skills as they embark on their thesis research as described above. Second, NRAO staff scientists collaborate with university astronomers in the supervision of Ph.D. thesis projects. Awards, typically of two years duration, are made to graduate students for residence at the appropriate NRAO sites, taking data, reducing it, and writing their thesis all under NRAO guidance. This program is highly valued by faculty in

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universities unable to support this kind of position otherwise, and by NRAO staff for the excellent student interaction it generates.

In addition to graduate summer students and resident graduate students, more than 100 Ph.D. students make observations with NRAO telescopes each year. Short stays of one to three weeks at the site, travel reimbursement, and computing facilities are provided to assist any students using NRAO facilities.

In 2002 the NRAO instituted a program to provide financial support to students performing research programs on the Green Bank Telescope. Graduate or undergraduate students at U.S. universities are eligible for the program. The primary objective of the program is to foster the training of a new generation of telescope users. The program is designed for one-year research projects, although two-year thesis projects may be considered. The funding cap is $35,000, which includes the direct stipend for student support, miscellaneous expenses such as computers and travel, and up to $3000 to offset the cost of administering the program at the university.

The program has received a strong response. Since its inception, 27 students have been awarded support stipends. In FY2004 nine students received awards, and approximately $335,000 was expended from Observatory operational funds toward this program. We anticipate a program of similar size in FY2005.

Jansky Fellowships

Postdoctoral astronomers are given Jansky Fellow positions with a term of two years that may be extended for a third year. In the selection process, recent graduates are given preference over those applying for a second postdoctoral position. Jansky research-associate appointments are available not only to radio astronomy students but also to recent Ph.D. recipients in engineering and computer science. Jansky Fellows formulate and carry out investigations independently or in collaboration with others within the wide framework of interests of the Observatory.

August 2004 marked the beginning of the traveling Jansky Fellowship program similar to the Hubble, Chandra, and Spitzer Fellowship programs. Traveling Fellows may work at any U.S. research institution. The 2004 traveling Jansky Fellows and their host institutions are A. Baker (University of Maryland), S. Chatterjee (CfA), T. Cheung (MIT), and N. Miller (Johns Hopkins University). In addition, three new resident Jansky Fellows will work at the NRAO in Socorro: V. Fish, N. Kanekar, and J.-P. Macquart. All Fellows were selected by a committee of scientists from external U.S. research institutions and from the NRAO. Both types of Jansky Fellowship include discretionary research budgets. An annual Jansky symposium is held at the NRAO to foster interaction among the Fellows and the NRAO staff. The Jansky Fellowship program is intended to prepare the Jansky Fellows to assume leadership positions in the U.S. astronomical community and to promote the health of radio astronomy in the U.S. An annual review is held to evaluate the progress of the Fellows. In 2005 we expect to appoint a total of six new Fellows.

Visitor Program

The NRAO encourages Ph.D. scientists and engineers in radio astronomy and related fields to visit any of its sites. We particularly encourage visits by young scientists who are faculty members at colleges and universities, scientists affiliated with NASA missions, foreign scientists, and senior scientists. The terms of a visit are negotiable, ranging in duration from weeks to months. The purpose of the visit can be for interaction with one or more NRAO staff members, summer visits for research, or sabbatical visits.

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Overview

Observatory Data Management was re-organized in 2003 to provide better responsiveness and closer focus on the needs of the major projects and operational telescopes. Software development is now managed by the projects and sites. In New Mexico the Interferometry Software Division (ISD) has been created to work on problems of interferometric data acquisition and analysis that are relevant to the VLA, VLBA, and the EVLA, and that have commonality with the efforts currently in progress in support of ALMA. The same group has been active in developing the Proposal Submission Tool for Observatory- wide application; its first release will be in support of observations using the GBT. The ISD has authored the NRAO on-line archive which currently contains all VLA data and will eventually include VLBA and GBT data. A Single Dish Integrated Product Team has been created in Green Bank and draws on support elsewhere to address issues relating to the acquisition and analysis of data obtained using single dishes. Computing services are coordinated centrally. Oversight of all computing resides with the Observatory Computer Council (OCC) appointed by and advisory to the Director. A number of forward-looking observatory-wide projects have been initiated by the OCC.

Software Development

End-to-End Processing (e2e)

For all telescopes, there are common features to the software needed to take a project from an initial proposal submission for observing time to a final scientific result. This includes all aspects of telescope operation from observing proposal handling, observation scheduling, real-time control and data acquisition, pipeline processing, archiving, and post-processing.

There have been small efforts in the past to consolidate the major common elements for existing telescopes. ALMA has proposed and largely funded a complete e2e capability. A team representing all present and future telescopes of the NRAO has been assembled to develop a common set of requirements to enable the differences between the telescopes to be consolidated into a single Observatory e2e framework. Plans for, and progress on, individual elements are included in the following sections.

Future Post-Processing Software

Astronomical data processing software is essential to the production of research-quality results from data taken by modern astronomical telescopes. There is some concern that the existing software packages used for this in radio astronomy will not be suitable for the computing environment of the future or for the development of the new algorithms needed to keep the NRAO's telescopes at the forefront of astronomical research. A small group representing all of the NRAO instruments is evaluating different future-development scenarios.

Project-Based Software Development

Proposal Submission Tool

The project to develop the Proposal Submission Tool for all current and future NRAO telescopes was started within the Interferometry Software Division (ISD). Since the GBT has the most pressing need for such a tool, initial development is focusing on this instrument without losing sight of the requirements of

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other projects and instruments. The tool is based on a Strategy and Architecture document formulated in early 2004. This was followed by successful negotiations between the ISD proposal-tool team and its UK-based ALMA counterpart which resulted in the adoption of common architectural principles and implementation. Early test versions of this tool were released June 1, July 1, and August 1, each of which underwent extensive testing by a core group of testers. The first major milestone was the release of a proposal submission tool for selected GBT staff use on September 1, in time for testing at the October 1 GBT proposal deadline.

Extensive GBT-specific testing of the proposal submission tool will continue well into FY05 before the tool is released to the general GBT user community. It is only after this stage that the tool will be expanded to allow proposal preparation for the VLA and VLBA, which we aim to release to select users in spring 2005. Significant work on handling EVLA and ALMA proposals is not expected until FY06.

GBT Configuration and Ease of Use

In FY2004 application programming interfaces (APIs) were developed to configure and observe with the GBT in a manner that is easy and intuitive for astronomers. This enables observer scripting and facilitates automated queue execution. At the beginning of FY2005, Scheduling Blocks which employ the APIs will be used to automate software regression testing and all-sky pointing observations. The new observing system will be introduced to visiting observers and will replace the GUI screens and Glish scripts that have been in use for the past few years. This is the first step towards automated queue execution, which will be implemented during the year by using the ALMA Observing Tool with minimal customization. Remote observing, which was specified during the previous year, will also be made available as a capability to GBT observers.

Single Dish Data Export and Analysis

Over the past year, the Single Dish Software Integrated Product Team (SDIPT) in Green Bank developed and delivered a consolidated FITS data product which helped to enable data export into the CLASS and IDL reduction packages. Additionally, standard observing modes and data-reduction cases were specified. In FY2005 a beta version of IDL modules for basic continuum and single-dish data analysis will be delivered for testing, after which a production version will be released to visiting observers. Building on these developments and the work that is being done by the Synthesis IPT in Socorro, a prototype pipeline will be developed in the upcoming year to process and display images generated by the Penn Array Receiver as well as by on-the-fly (OTF) mapping. Data quality information will also be generated during the period for future storage within the archive.

AIPS

AIPS (Astronomical Image Processing System) remains the backbone data-processing software for the VLA and VLBA, the two operating interferometers at the NRAO. In FY04, as for a number of years, the primary activity of the AIPS group has been to support external users of the software package. This includes the development and support of scripts that enable hundreds of institutions worldwide to host an AIPS installation as well as maintenance of a help desk that is used for bug reports, user suggestions for enhancements, and questions such as “How do I do XXX with my data?” Near the end of the first quarter of FY04, a frozen 31DEC03 version of AIPS was released to the community, and the new 31DEC04 version, updated daily via a “midnight job,” was initiated. Figure 9.1 summarizes the downloads of AIPS

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by remote users from late in calendar year 2003 through early August 2004; note the total of well over 800 unique computer addresses that have accessed AIPS during an eight-month period.

Figure 9.1. Cumulative record of downloads of the AIPS software during the last month of calendar 2003 and the first seven months of calendar 2004. From the top, the four captions and their associated lines indicate (1) the total number of unique computer addresses accessing the AIPS software, (2) the number of such addresses accessing the “midnight-job” version of 31DEC04 to update installations with new changes to the code, (3) the number of addresses accessing the complete set of 31DEC04 AIPS files for installation, and (4) the number of addresses downloading the frozen 31DEC03 version of AIPS for installation.

During FY04 the small AIPS group has done many things to make AIPS easier to use and, in modest ways, more powerful. There are two major themes: to build tools to function in pipeline (automated data reduction) environments and to create more sophisticated calibration methods for interferometric data. Pipeline tools for polarization calibration, setting imaging parameters, and model fitting were completed. Improvements were made in atmospheric amplitude calibration of VLBA data, in the use of new weighting methods and overlapping intervals in VLBI and VLA calibration, and in fitting for and removing residual delays and phases due to the atmosphere and ionosphere. Models of some VLA calibration sources at high frequencies are now provided within AIPS. The documentation for AIPS is now available in PDF and HTML forms, and help files may be displayed and cross-linked in web browsers. Adjustments to the data-reading tasks were made to handle the new world-coordinate nomenclature (of critical importance to the National Virtual Observatory) and to deal with the diversity of data now available from the VLA archive. AIPS now supports read-only devices such as DVDs, runs effectively on MacIntosh OS/X computer systems, and requires much less human intervention in the automated updating of AIPS systems.

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In FY05 the AIPS group again will support the user community reducing data on the major NRAO interferometers. A frozen release of the 31DEC04 version will be made near the end of the first quarter and 31DEC05, the new version subject to daily updates, will be initiated. New development will continue along the major AIPS themes: pipelines, improved calibration, and enhanced user convenience and functionality. In particular, automated data editing using parameters found from the data will become available and should become part of the pipeline systems already present in AIPS. Work on improved atmospheric opacity modeling, correcting VLBA positional measurements of satellites and other sources, and providing more and better calibration-source models should produce better calibrations of both VLA and VLBA data. We expect to make available a binary distribution of AIPS for MacIntosh computers using the excellent proprietary IBM Fortran compiler. For the EVLA, investigations of new/improved imaging algorithms, including those dealing with spectral index and multiple pointings, will be begun.

Science Software Group

In FY04 continuing improvements were made in performance of the AIPS++ code-base along with steady progress in development of ALMA priority-1 requirements (core interferometric reduction applications). The main performance improvements were in the basic calibration facilities, where improvements of 2-5 in speed were made under different test cases; changes in the use of I/O provided the bulk of the improvements.

Additions/improvements in the functionality were made in areas of calibration, imaging, image analysis and data editing (see http://projectoffice.aips2.nrao.edu for details). ALMA TST1 (Test 1) was passed, which provided an external test of single-field interferometry reduction (based on analysis of VLA and Plateau de Bure Interferometer datasets). ALMA CDR2 (Critical Design Review 2) also was passed; the review panel recommended that development continue with the AIPS++ code base to provide the ALMA data-reduction package. A framework migration plan has been developed to replace the existing custom Glish framework with ACS (ALMA Common Software) built on robust industry standards (e.g., CORBA).

In FY05 the Science Software Group will continue development of the core interferometric applications, focusing on mosaicing and combined single-dish/interferometer reductions. Two scheduled external- scientist tests will take place to evaluate the progress (using VLA, GBT, and BIMA data). Key development areas will be in improving the calibration facilities (incremental calibration, improved interpolation routines and enhanced performance) and in data selection and editing (for improved automated flagging in pipeline/offline use). A packaged distribution of the AIPS++ applications within the ACS framework will also be made.

Data Storage and Retrieval

Data Archive

The NRAO on-line Data Archive began operation at the start of FY04; it allows everyone on-line access to all VLA data and some VLBA and GBT data (http://archive.nrao.edu/archive). In the first nine months of operation, over 350 users from 175 institutions downloaded over 10,000 telescope data files. The download data rate is about 100 Gigabytes per month. A snapshot of the cumulative archive downloads during the first year is shown in Figure 9.2. Data files over 12 or 18 months old are in the

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public domain (see the URL below for details) and accounted for 3/4 of the file downloads. The data files reside on a hard-disk array and provide the archive users with fast access and downloads via FTP.

Figure 9.2. Plot of the cumulative number of data files downloaded from the on-line VLA data archive since mid-October 2003. Approximately 70% of the downloaded files are public data, but only about 50% of the Gigabytes (not shown) are from publicly accessible data, since the older data sets are fragmented into more and smaller files in the archive.

Currently the archive contains all VLA data going back to 1976, raw VLBA data going back to June 2002, and some calibrated VLBA data going back to December 2002. Efforts to extend the VLBA archive back to 1992 are underway. There is a small amount of GBT data available now from 2002 and 2003. Complete archiving of raw GBT data awaits final definition of the SDFITS (Single-Dish Flexible Image Transport System) format.

A new NRAO-wide data archive policy has been written and may be found on the web at http://www.nrao.edu/administration/directors_office/dataarchive.shtml. The new policy shortens the proprietary period from 18 months to 12 months for 200 proposals submitted at the official proposal deadlines occurring since the beginning of FY04; these deadlines for the NRAO occur at the beginning of October, February, and June. This shortened proprietary period is in line with those at other major observatories such as NASA’s Great Observatories.

The development of the NRAO Archive is proceeding in phases. The first phase is essentially complete; that is, we now provide users with access to all VLA data and with tools to identify and download the data that they want. The next phase is to make the archive scientifically more useful to a wider range of astronomers, especially non-radio astronomers. To that end, the Data Archive Integrated Product Team is discussing several issues: improvements to the user interface, more descriptive display tables and automated data-reduction pipelines which could produce calibrated data and useful images. Much of the

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development work for the Data Archive took place under the auspices of a separate grant that now has expired, so we anticipate that the improvements to the user interface and search capabilities will be rather limited.

During FY05 we aim to expand the NRAO Data Archive in several areas: (1) Complete the transfer of the VLBA raw data tape archive to the online disk array (approximately 10 TeraBytes); (2) Complete the archive mirror site at the National Center for Supercomputing Applications (NCSA). Users will be able to select and download any archived data from the NCSA site as well as from the NRAO-hosted archive; (3) Provide archived data from the GBT through the NRAO Data Archive; (4) Expand the archive infrastructure to receive test data from the EVLA WIDAR prototype correlator; (5) Provide a better interface to the National Virtual Observatory (NVO). Given the resource limitations, it is likely that items (1) and (3) will not be completed until at least FY06.

Virtual Observatory

The goal of the Virtual Observatory (VO) initiative is to link astronomical archives worldwide to enable large-scale, distributed multi-wavelength data analysis by providing uniform access to data regardless of location or waveband. Observatories such as the NRAO produce data products and “publish” them to the VO; the astronomer then can use community-developed VO data-analysis software to locate and analyze data regardless of their source. The NRAO is a partner in both the U.S. National Virtual Observatory (NVO) and in the International Virtual Observatory Alliance (IVOA). The focus of effort over the past year has been development of the VO infrastructure. The primary responsibility of NRAO is to define the data access protocols used by client data-analysis software to access and analyze data in remote archives. In the past year a service architecture has been defined and protocols have been defined and implemented for accessing catalog, image, spectral, and time-series data. A start has made to define data-model standards for interferometric data.

A major focus of VO development currently is development of standard data models for astronomical data and mapping these models into external representations such as XML and FITS. The NRAO will continue to participate in the development of these standards. All of the VO data-access protocols will be reworked in 2005 to conform to the evolving VO standards. A general query language capability, now under development elsewhere in VO, will be integrated into all the VO data-access protocols to provide a more sophisticated data discovery capability. The next step after defining standard data-access protocols is to provide reference code which implements these protocols. As part of this effort we are designing a scalable data access framework. This will be used both in an archive front-end to implement the data- access services, and in client data-analysis software (such as AIPS/AIPS++ within NRAO) to provide a portal to the VO for data-access and analysis. NRAO is also working to define standard data models and export-data formats, conforming to VO standards, for data from the NRAO telescopes.

An effort is underway to pipeline-process data to produce reference images for some trial subset of the data in the VLA archive. These images then would be published to the VO and would enable experimentation with radio data within the VO, beyond the classic NVSS and FIRST catalogs which already are accessible. As part of the archive project discussed previously, we have constructed an exposure-time map of all observations that have been made with the VLA during its history; this is shown in Figure 9.3. The VLA has observed in virtually every one of the accessible 30,000+ square degrees in its lifetime of more than 25 years, running many thousands of observing programs in a large number of different observing modes. Retrospectively calibrating and imaging a significant subset of the archive

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data represented by this sky map would be a daunting task. During FY05, the loss of two key scientific staff members to sabbatical leave will limit our ability to make progress on the reference-image project.

Figure 9.3. All-sky exposure map of the data in the on-line VLA archive, averaged over each square degree in the sky. Dark regions have total integration times of less than 300 seconds. The Galactic Plane and (surprisingly) the Ecliptic Plane show up prominently in this representation of historical VLA observing.

Central Computing Services

Overview

Central Computing Services is coordinated by the Computing and Information Services (CIS) division. The mission is to plan an optimum computing and network environment for the users of the NRAO’s telescopes, for the operation of those instruments, and for the development of new facilities. CIS sets policies and standards in this area, and coordinates relevant activities across the Observatory. CIS supervises the maintenance of all computer equipment and software observatory-wide and maintains a budget to provide these services.

The sites and major projects (Green Bank, Socorro, Tucson, ALMA) each have a computing division charged with providing local support and reporting to the local site director or project manager, as appropriate. Operational funding for them is through the sites and projects. CIS augments and coordinates the activities of the computing divisions. A key mechanism has been the CIS Executive Committee (CISEC) consisting of the heads of computing for the various NRAO sites and for the major development projects.

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Computing Security

The adoption of a solid computer security policy is a pre-requisite to securing any enterprise from online threats. Since 1999, the NRAO has had in place such a policy, which provides a framework to balance the conflicting requirements of accessibility for the radio astronomy community and the public with the need for high security.

All of the NRAO operational sites are networked together. It is therefore essential that security be maintained at all sites; lack of diligence at one site will otherwise compromise the security at all sites. This is achieved through the security policy by a Computing Security Committee (CSC) composed of a Computing Security Manager (chair and CIS staff member), two representatives chosen by each of the four main NRAO sites, the chief NRAO network engineer, and Liaisons from each of MIS (Business computing), the Safety Committee, and Scientific Staff.

The CSC has specified and implemented detailed practices to minimize the security exposure. Since the implementation of these practices, there have been no serious computer security incidents. However, intrusion attempts, probes, viruses, spyware, and similar attack attempts continue to come from the Internet with a seeming exponential increase in frequency, scope, and sophistication. The threat from mobile and wireless equipment brought by visitors is widely acknowledged in the computer industry, and is also being addressed in the context of the committee and the security policy.

We will continue to improve education and documentation for NRAO computer users. We will maintain and enhance the security measures already in place. In addition, we will maintain Virtual Private Networking, which allows travelers and telecommuters to become part of the NRAO internal network securely.

Observatory-wide Coordination

Computing Standards and Policy

To provide a uniform structure in which to carry out our mission, CIS will continue to develop and enforce standards, policies, and conventions originally formulated and adopted by its predecessors. Policies include Computer Use, Major Software Procurements, Computer Hardware Purchasing, etc. Standards include computer hardware configurations and lists of standard software applications.

Common Computing Environments

The Common Computing Environment (CCE) is a major initiative started in 2000 to minimize the differences, often historic, in computing environments between the NRAO's main sites. Such differences have in the past resulted in unnecessary incompatibilities, duplication of effort by computing staff, and confusion for users who work on systems at multiple sites. The CCE effort was renewed in 2002, reshaped into an “accelerated” program, and this phase of the project was substantially complete at the end of 2003.

As computer environments are never static—new versions of operating systems are released, new capabilities become widespread in the industry—the coordination started by the CCE project is continuing through regularly scheduled meetings and online collaboration. This operational phase of the CCE will need to continue indefinitely.

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Contracts

It is clearly advantageous that widely-used software, such as office suites, computer-aided design software, and operating systems are kept at the same revision throughout the observatory. This greatly simplifies document interchange and package support. A major activity of the CIS is to maintain contracts for these software contracts. Further, CIS is responsible for maintaining contracts for key hardware components - computers, printers, routers, etc.—and for the frame relay intranet service. By consolidating licenses or equipment from multiple sites under a single budget, we reduce the overhead of managing these contracts, simplify the process of obtaining software upgrades, and can often negotiate better discounts with vendors. This amounts to approximately sixty contracts annually.

Digital Infrastructure

There have frequently been cases where the computer needs of the local computer divisions are in excess of their local budget. Traditionally, we have tried to make note of large new initiatives and to attempt to fund them from a separate budget that is centrally administered. No funds have been allocated to this endeavor, but we will continue to coordinate such interests with a view to seeking funding for them should the opportunities arise.

Recurring Cost

Outside the construction projects, the NRAO has computer and associated equipment that is valued at roughly $2.4M. This equipment has a lifetime of no more than five years. Thus, a budget of no less than one-fifth of this amount is required to address depreciation. The practice of maintaining a central budget for replacement equipment needs to be continued. This includes the whole spectrum of equipment from powerful systems for scientific visitors, servers, all the way down to desktop personal computers. At the desktop, when new equipment is acquired, it has been traditionally given to those who need the highest performance and trickle down the systems to less demanding users so that the oldest, slowest computers can be discarded.

Observations continue with the VLA, VLBA, and the GBT; data is written into the on-line archive as it is observed. This means that we have the additional recurring cost of adding disk space to the archive regularly.

Coordinated Activities

We intend to continue the practice of maintaining a central budget to cover training fees for any computer professional at any site. To foster communication and collaboration between computing staff at the various NRAO sites, we will provide funding for their inter-site travel. This budget will be available to cover the travel expenses involved in bringing together a large number of NRAO computing staff involved in specialized computing fields such as real-time development or system administration.

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Information Infrastructure

Web Services

The significant improvements made in the past two years to the NRAO's web infrastructure—as a result of deployment of deploying four identical servers running identical web server software (Apache) at each main NRAO site—continue to mount. The content of the NRAO's main web presence (www.nrao.edu) is regularly mirrored so that each site's server has the same content for their local users. For a user from outside, the servers employ a simple load-balancing scheme, providing service from the three sites that are directly connected to the Internet (all but Green Bank).

The standard style for official NRAO web pages continues to be applied to new content, and to be retrofitted to older content as needed and as time permits.

The repository of radio-astronomy-related images in the NRAO Image Gallery operated by the Education and Public Outreach (EPO) division continues to grow, and the service itself has been operating without any problems. A new “Radio Astronomy Picture of the Day” has been added to the NRAO's main home page.

Several instances of web-based collaboration software known as a “wiki” have been created within the NRAO. This software has already helped individuals, groups, and projects within the NRAO to perform a variety of collaborative tasks including project management, reporting, and software development. We expect the growth of use of this collaboration in the coming years.

A web-mail interface was added as a prototype in 2004, but became so popular it has been converted to a mainstream supported service. This permits staff members to access their mail in a safe and secure way from any web browser on the internet. We will continue to implement cost-effective solutions to provide remote access to the NRAO computers by its traveling staff.

With EPO, we propose adding a full-time Webmaster position to provide the necessary technical leadership to keep the NRAO's web presence at a high professional level by following new technology and providing tools to web authors.

Other Services

The NRAO now has a unified calendaring system for scheduling internal meetings, colloquia, and other significant events. Other uses for this system will be pursued. We have developed a common directory access protocol to provide accurate, up-to-date staff information, including a phone book, for the entire observatory. We expect to be able to build on this service to provide common services to all staff.

Networking and Telecommunications

In the last two years, we have consolidated many of our long distance phone services under a single contract through the General Services Administration (GSA) Federal Telecommunication Service (FTS2001) initiative. In addition, we provide web meetings, audio conferencing, international and domestic toll-free service, and calling cards to our employees under this program. This provides the most cost-effective service available. However, prices and available features are changing constantly, so continuous monitoring of service contract options is necessary.

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The Local Area Network (LAN) in Green Bank has been greatly enhanced in the past few years. However, the Ethernet switches that are the backbone of this LAN are aging. We propose to continue a program to replace and upgrade the units over the next year or two. A major upgrade of the LAN in the AOC is in progress in Socorro. When completed, this will provide Gigabit (GigE) service to all desktops. A similar project is underway in Charlottesville. It is expected that the additions to Stone Hall will be completed in late 2004. New construction includes a new communications room centrally located in the completed building. This will contain new routers and switches capable of providing GigE to the desktops. Locations in the new wing will be wired directly to this room. This includes copper connections and tubes through which fiber can be blown in the future. All rooms in the original building will also be re-cabled with connections to the new communications room.

Since 1996, the NRAO has had an intranet connecting most of its locations using a frame relay. Since 2001 the service has been provided by AT&T under GSA/FTS2001. This provides a reliable and secure backbone for all internal electronic communications between the locations. Since the requirements of the operations have grown since 1996, we regularly re-evaluate the bandwidth provided to the various locations. Increasing the bandwidth is, in many cases, merely a matter of cost. Decreasing costs have enabled us to increase the bandwidth to some sites cost-effectively in the last year, and we expect to be able to continue the process.

Through a special grant in 1999, we were able to deploy a small video communication network between the major sites using the intranet infrastructure. In 2001, we procured equipment to increase the number of systems to ten and we now routinely support concurrent video conferences. The video system is also widely used to relay scientific and technical colloquia throughout the observatory. However, the biggest remaining deficiency for interactive multi-site video between the auditoria is the auditorium sound systems. These will be upgraded in the next year. We will also investigate a more sophisticated video hub to give us better diagnostic capabilities and to allow us to run conferences from a studio if needed.

The NRAO is a sponsored participant in the Internet2 from all major locations. There are also many increased network connectivity requirements for future operations: the need to serve data from the archives for the presently operating instruments (VLA, VLBA, and GBT), the full deployment of the GBT spectrometer, the opening of the Green Bank Science Center (GBSC), the development of the ALMA science center in Charlottesville, the connectivity from Charlottesville to the operational sites in Chile, and the EVLA deployment. A study is underway to integrate these needs into a coherent whole for future network connectivity.

Headquarters Computing

The NRAO Charlottesville Computing Division's mission is to provide the computing services to the local NRAO staff and scientific visitors to Charlottesville. The local groups served by the computing division include the Director's office, Education and Public Outreach, scientific services, the Central Development Lab (CDL), the Human Resources office, the business office, Charlottesville ALMA staff, the Program Office, and the Charlottesville-based software development staff. The support includes electronic mail, printers, central servers, centralized data storage, data backup services, software installation and support, computer configuration and procurement, remote access capabilities (dial-up modems, etc.), web services, directory services, network management, phone service, and application software support.

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In the coming year, this support will be in the context of the general relocation of personnel due to new office locations and renovation of Stone Hall. It will take significant effort to minimize the disruption caused by the personnel and equipment relocation. In particular, it is our responsibility to ensure that all staff has appropriate availability of computers, servers, printers, phones, and networking before, during, and after relocation.

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Overview

The National Radio Astronomy Observatory’s education and public outreach (EPO) program provides leadership for the development of a scientifically and technically literate society; communicates extensively with the professional astronomical community, the general public, and educators about radio astronomy via modern print and electronic media; functions as an exceptional resource for K-12 science education; and develops innovative astronomical educational programs for the general public and university educators. The NRAO EPO staff coordinates and promotes astronomical education and public outreach activities observatory-wide.

The NRAO EPO staff currently includes three full-time and one part-time employees in Charlottesville, six full-time and nine part-time employees supporting Green Bank Science Center operations, and three full-time and one part-time employees in New Mexico. In FY2005 a member of the NRAO Charlottesville scientific staff will actively participate in the Observatory’s education and public outreach efforts as an “EPO Scientist,” functioning as a scientific advisor to the EPO team.

The NRAO FY2005 EPO program plan is ambitious, forward-looking, and vigorous, combining new initiatives with a wide range of proven continuing programs. In FY2005 EPO staff will initiate the Legacy Imagery Project; develop a program to bring NRAO science, education, and public outreach into museums; and expand its leadership and activities for the ALMA EPO Integrated Project Team (IPT). The NRAO EPO program in FY2005 will also include: (a) improvements to the NRAO web site; (b) revision of key NRAO brochures; (c) improved communication and interaction with the international professional astronomical community; (d) continued participation in national and international astronomical outreach consortia; (e) press releases on a broad range of radio astronomy topics; (f) operations, exhibit, and revenue improvements at the Green Bank Science Center and the VLA Visitor Center; and (g) innovative education programs for the general public, K–12 science teachers, and educators at the university level. Each of these NRAO EPO efforts is described in the following sections.

New Initiatives

In FY2005 the NRAO EPO program will initiate two new projects: a Legacy Imagery Project and a program to bring NRAO science and outreach to major museums in the United States. Each of these projects has been developed in response to recommendations made by the NRAO/AUI Visiting Committee.

NRAO Legacy Imagery Project

The Legacy Imagery Project will develop an in-house capability to distill and process astronomical data acquired at radio wavelengths into compelling visual imagery of objects in the astrophysical zoo, such as molecular clouds, gaseous and planetary nebulae, supernova remnants, interacting galaxies, and galactic jets. Source data will be acquired at one or a combination of the Observatory’s research facilities—the Very Large Array (VLA), the Very Long Baseline Array (VLBA), and the Green Bank Telescope (GBT)—and the NRAO data archive will be extensively mined.

Many astronomical targets for radio-wavelength imaging, however, are inadequately represented in the NRAO archive. Generating compelling images for some astronomical objects may require some observing time at an additional wavelength or VLA configuration. In such cases, the Legacy Imagery

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Project team will collaborate with the EPO Scientist on a proposal for additional VLA, VLBA, or GBT observing time. Whenever possible, these EPO-motivated observing proposals will be mated to a scientific proposal. The Hubble Heritage Project, for example, routinely receives observing time on the Hubble Space Telescope to add one or more colors to their target’s available dataset or to increase the imaged field-of-view so that a more recognizable portion of an astronomical target is available.

A meeting between NRAO EPO staff and members of the Hubble Heritage Project team has already occurred (July 2004), providing an opportunity to review and discuss with our STScI counterparts the techniques and resources required by the successful Hubble Heritage Project. This meeting also yielded a proposal for an NRAO - STScI collaboration to create a Heritage-style joint radio-optical image. NRAO EPO staff will aggressively pursue this opportunity in FY2005. The timeline for producing a joint radio- optical image will depend on the selected target, which will be determined in follow-up meetings between the NRAO and Hubble Heritage personnel in September and October 2004. The issues encountered in creating visually compelling imagery from radio data are significantly different from those seen with optical data. The FY2005 Legacy Imagery Project will attack these issues, seeking innovative solutions.

Figure 10.1. A multi-wavelength Centaurus A composite image: radio 21 cm line emission (pink), radio continuum emission (green), x-ray emission (blue), and optical (yellow and orange) data.

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Images produced by the Legacy Imagery Project will be designed to fire the imaginations of the general public and educators while improving their understanding of the NRAO and its mission and arousing their curiosity about the universe we inhabit. These images will be key components of education and public outreach efforts at the Observatory and will be imported into the NRAO Image Gallery. Since the STScI devotes the equivalent of approximately three full-time personnel to the Hubble Heritage Project, which releases one image per month, the Legacy Imagery Project’s goal is to produce two high-quality images in FY2005.

Science Museum Outreach

In FY2005 the NRAO EPO program will initiate a new program that will extend NRAO science and outreach to major museums and planetariums in the United States. EPO staff will package visually compelling Observatory data products and radio astronomical imagery—e.g., the VLBA movie of SS433 produced by Mioduszewski et al. at NRAO in 2004—with multimedia educational and display materials. These NRAO EPO products will be offered for distribution to science museums and planetariums as traveling exhibits.

The NRAO EPO staff will also generate multimedia packaging and distribute other education and public materials, such as the recently produced ALMA DVD, to science museums and planetariums. Since electronics list servers are an efficient means to contact the planetarium community (Dome-L list-server) and the science center community (ASTC list-server), EPO staff will use these to identify and contact potential venues.

The first multimedia traveling exhibit package is scheduled to be ready for distribution by February 1, 2005.

ALMA

North America and Europe have formed an Integrated Project Team (IPT) to lead education and outreach efforts for the Atacama Large Millimeter Array (ALMA) with NRAO in the leadership position. This IPT will coordinate ALMA press releases with our European partners, distribute a 15-minute ALMA DVD in North America, distribute an ALMA public brochure, and create an ALMA display for use at professional astronomical meetings. This display will debut at the January 2005 AAS meeting, which will also feature an ALMA Town Meeting supported by the Observatory’s EPO personnel. FY2005 will also see the production of a large-format ALMA science brochure and the creation of a unified ALMA website with links to all partners. EPO staff will continue their support of the North American ALMA Science Center and will incorporate the scientific excitement and promise of ALMA into all NRAO education programs.

NRAO staff will conduct monthly teleconferences with their European counterparts to resolve ALMA EPO IPT issues, exchange ideas, coordinate tasks, and formulate future plans. Among the numerous ALMA EPO opportunities in FY2005 will be the possible addition of Japan and the Enhanced ALMA capability to the project, the ALMA antenna procurement, and the acquisition of first fringes.

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Figure 10.2. A panoramic view of the Llano de Chajnantor, the ALMA site.

NRAO Website

The NRAO website is a critically important window to the outside world and is the primary point-of- contact between the Observatory and its four key constituencies: the general public, teachers and students, professional and amateur astronomers, and NRAO employees.

The Observatory has, in the past several years, invested significant resources in the creation and continual improvement of its website. Additional investments and changes will be made in FY2005. As the North American ALMA Science Center sharpens its mission definition and activities, it will become an increasingly prominent component of the NRAO website. As the Legacy Imagery Project moves forward and generates visually compelling images, the project and its product imagery will be prominently featured at the NRAO website.

The NRAO website’s effectiveness and graphics will undergo a comprehensive internal and external review, seeking a marked improvement in the site’s navigability, content, innovation, and ease-of-use.

On-line activities and resources, such as “Who’s Using the Telescope Today”, will be improved. The website will be modified to include real-time webcam images of the GBT and the VLA, joining the real- time imagery of the VLBA antennas and the ALMA ATF already available at the NRAO website. Effort will also be invested in improving the NRAO Image Gallery, with the implementation of more rigorous image-quality criteria and the proactive solicitation of quality imagery from the NRAO user community.

NRAO Brochures

In FY2005 EPO staff will undertake a significant revision and improvement of several NRAO brochures that are distributed to the general public and the professional astronomical community.

Each of the NRAO’s operational facilities—the GBT, the VLA, and the VLBA—is described by a pair of EPO brochures: a smaller tri-fold “rack” brochure aimed at the general public, teachers, and students; and a larger “science” brochure targeting prospective telescope users and other scientists. In FY2005 EPO staff will re-evaluate the effectiveness of both versions of each of these facilities brochures, then update, rewrite, produce, and distribute a revised brochure set to the venues that stock these brochures.

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A small-format general information brochure about the NRAO and a large-format NRAO science brochure will also be completed in FY2005. Finally, a larger ALMA science brochure is being developed with our ALMA partners. If Japan joins the ALMA project, the ALMA public brochure will also be revised.

Figure 10.3 A recent ALMA brochure.

Astronomical Community

The NRAO EPO staff will continue to improve its communication to and interaction with the international professional and amateur astronomical community. NRAO’s participation in the semi- annual American Astronomical Society meetings as an exhibitor and pressroom coordinator and its participation in focused astronomical consortia are vital to these goals.

American Astronomical Society (AAS)

The NRAO EPO staff will continue to be proactive participants in the semi-annual American Astronomical Society (AAS) meetings. In FY2005 AAS meetings occur in San Diego (January 9 – 13, 2005) and Minneapolis (May 29 – June 2, 2005). These AAS meetings will be important venues for NRAO, providing opportunities to interact with graduate and undergraduate students, astronomy and physics faculty, post-doctoral fellows, and research staff from across the U.S. astronomical community.

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The large multi-element NRAO exhibit and display booth was comprehensively re-designed for the June 2004 AAS meeting to improve its visual impact and attractiveness.

Figure 10.4. Miller Goss discusses NRAO facilities and capabilities with prospective users at the NRAO exhibit at the Atlanta AAS meeting (Jan 2004).

At each AAS meeting EPO personnel staff the exhibit and display booth, assisted by members of the NRAO scientific, technical, and management staff. NRAO personnel look forward to these opportunities to discuss the Observatory’s research facilities, capabilities, and programs with the U.S. astronomical community and answer questions from prospective users. A complete set of NRAO science and facility brochures will be available for meeting attendees.

An ALMA Town Meeting is scheduled for the January 2005, San Diego meeting and EPO staff will be present to facilitate and promote this event. A separate ALMA display and exhibit is being designed and built for this Town Meeting and for other meetings that offer ALMA EPO opportunities.

The AAS meetings attract numerous science reporters. To ensure that NRAO scientific results receive excellent media coverage, EPO personnel invest considerable effort in AAS press-room coordination and assistance.

Astronomical Consortia

The NRAO will continue to actively participate in the Southwest Consortium of Observatories for Public Education (SCOPE). Member institutions include the Kitt Peak National Observatory, Whipple Observatory, McDonald Observatory, Apache Point Observatory, and the National Solar Observatory. SCOPE has raised funds from public and private sources to produce astronomy education materials.

In FY2005 the NRAO will also continue its participation in STARTEC (State of the Art Telescope Educational Consortium). Member institutions include the Gemini Project, Jodrell Bank Observatory,

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Arecibo Observatory, Gran Telescopio Canarias, the European Southern Observatory’s Very Large Telescope, the South African Astronomical Observatory's Southern Africa Large Telescope, McDonald Observatory's Hobby-Eberly Telescope, the Subaru Telescope, Keck Observatory, Joint Astronomy Centre, Mauna Kea Astronomy Education Center, Mauna Kea Visitors Information Station, Royal Observatory of Edinburgh, and the Herzberg Institute of Astrophysics. By sharing resources and expertise, STARTEC enhances individual education and public outreach activities and conveys the excitement of astronomy to a worldwide audience.

Amateur Astronomers

Amateur astronomers are a proven resource for education and public outreach. The NRAO has forged close ties with New Mexico's extensive amateur astronomy community. In FY2005 the NRAO will provide VLA tours and lecturers for the 11th annual Enchanted Skies Star Party, a well-attended event in Socorro. NRAO will also expand its program of providing NRAO-labeled donations as door prizes for major U.S. amateur Star Parties.

Also in FY2005 NRAO-Green Bank will host the second annual StarQuest star party in partnership with West Virginia amateur clubs. In July, 2004 approximately 150 adults registered for the multi-day event.

The NRAO also benefits from its association with the amateur radio community, which boasts 600,000+ licensed U.S. operators. In FY2005 the Society of Amateur Radio Astronomy (SARA) will again hold its annual conference at Green Bank. SARA members are active supporters of radio astronomy outreach. Using castoff satellite dishes and electronics, for example, SARA has developed and donated low-cost demonstration radio telescopes to museums and classrooms. The Green Bank site has one system of this type, the “Little GBT.”

Figure 10.5. A recent “Little GBT” demonstration at the Green Bank Science Center.

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Media Relations

Assuring that news stories about the NRAO and research performed with Observatory telescopes regularly appears in newspapers and magazines, and on television and the radio, is a vital EPO responsibility. EPO staff seek the widest possible dissemination of NRAO research results through the mass electronic and print media. This effort is time-intensive, requiring continual cultivation of reporters, editors, and contacts in the media, press rooms, and at press conferences.

The NRAO public information officers (PIOs) write and issue press releases, working closely with scientists, with Observatory management, and with the National Science Foundation (NSF) Office of Legislative and Public Affairs. NRAO press releases often generate coverage in major newspapers such as The New York Times and The Washington Post; and on cable, broadcast outlet, and even network television coverage. Wire-service stories resulting from NRAO press releases will appear in hundreds of subscribing news outlets.

Press releases feature the work of staff scientists and investigators from other institutions. NRAO PIOs often collaborate with press officers at external institutions and university press offices to produce either a joint press release or simultaneous individual releases. PIOs provide critical guidance to scientists on many aspects of media relations, e.g., the news-embargo policies of Nature and Science.

Figure 10.6. A recent article on the National Radio Quiet Zone and the GBT in Wired magazine.

Press releases are distributed by electronic mail to major news organizations, and via the AAS to 1,400+ science journalists worldwide. NRAO is experimenting with the AAAS’s Eurekalert press services for stories outside the normal interest of the AAS. All press releases and associated imagery are available on the NRAO website. Web-based news organizations, such as Space.com, link directly to NRAO press releases and images. Communication between EPO staff and NRAO’s user community is critical since EPO staff need to be informed of exciting research results at the earliest possible time.

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In an effort to reach the public at the grass-roots level, the NRAO launched a web-based “do-it-yourself” press-release form in FY2004. Schools, clubs, and tour groups that visit the NRAO sites can create and release a customized press release to their local newspapers. In FY2005 this form will be expanded to include the VLA, and other sites as appropriate.

EPO will host a National Science Foundation (NSF) - Public Information Officers Workshop in Socorro, October 21 – 22, 2004. Two dozen Public Information Officers from NSF will visit the AOC and VLA.

Visitor Centers

The visual impact of the NRAO telescopes and the educational value of self-directed exploration at our facilities make visiting NRAO sites a set piece in our EPO program plan. We are actively promoting public awareness of our research and mission through our visitor facilities, seeking increased attendance by casual tourists, motor-coach groups, and students.

Green Bank Science Center

FY2005 goals for the Green Bank Science Center are to increase attendance and gift-shop revenue by 10%. The winter months offer the greatest opportunities, given the abundance of wintertime visitors to established tourist destinations such as Snowshoe Resort. The Green Bank Science Center, entering its second year of year-round operations, will continue its collaborative marketing efforts with other local attractions and the county convention and visitor’s bureau. To encourage return visits, four new exhibits will be installed in FY2005.

The Science Center will be open daily from Memorial Day weekend through Labor Day weekend and Wednesday through Sunday after Labor Day. Free guided bus tours to the telescopes operate hourly from Memorial Day weekend through 31 October. There are three tours each day from 1 November to Memorial Day weekend. The onsite Café and the bunkhouse are proving increasingly popular and offer additional opportunities for revenue and program growth.

Figure 10. 7. The Green Bank Science Center

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VLA Visitor Center

The FY2005 VLA Visitor Center goals are to increase attendance and gift-shop revenue by 5%. This will require a vigorous marketing plan and advertising budget from the Education Officer and an increased use of free advertising resources by the Public Information Officer.

Another mechanism for increasing visitation is to provide additional scheduled guided tours for the general public. Gift Shop revenue will be used to hire part-time help to assist with guided school and special group tours during the busy seasons as well as to test-drive a plan for scheduled tours once each week. The Education Officer will devise and implement the plan with input from the gift shop staff, PIO, and business office. Updated exhibits will be installed. The Center will be open daily from 8:30 a.m. to dusk; the Gift Shop will be open from 9:00 a.m. to 4:00 p.m. and until 6:00 p.m. during peak summer hours.

Conceptual drawings for a new Visitor Center have been completed by the University of New Mexico School of Architecture and Planning. The proposal, including rationale, facility plan, business and marketing plans, and construction timeline will be completed and presented to observatory administration by mid-October 2004. Education

The NRAO educational programs contribute directly to the fullfillment of our mission to “to support the development of a society that is both scientifically and technically literate.”

Green Bank and Socorro will continue to offer their Chautauqua workshop programs for undergraduate faculty, in which over 500 college teachers have participated. Less-formal continuing programs allow college professors teaching astronomy to schedule observing time at either the VLA or the 40-foot antenna at Green Bank.

Figure. 10.8 NRAO/NMT teacher workshop participant with very small radio telescope she built during the course.

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In FY2005 the NRAO will be in the sixth year of its Research Experiences for Teachers (RET) program, funded by the National Science Foundation. Secondary-school teachers participate in this eight-week summer RET program, performing research in West Virginia, New Mexico, or Virginia.

The NSF funded RARECATS program will continue in FY2005 at Green Bank, giving K–12 teachers hands-on research experience. Teachers graduating from this program often bring their students to use the 40-foot Green Bank telescope. RARECATS and its predecessor workshops have reached more than 5,000 teachers.

In FY2004 Green Bank and Socorro received grant awards from NASA’s IDEAS program: Doing the Dishes, a teacher workshop program, and Quiet Skies. Activities developed for Doing the Dishes will be incorporated into a new Master of Science Teaching (MST) class in observational radio astronomy which will be offered at New Mexico Tech. Socorro’s N2 Instructional Interferometer and Small Radio Telescope will be made available for group use, especially through those teachers who participated in Doing the Dishes or the MST observational radio astronomy class in FY2004.

The Quiet Skies project will result in an inexpensive radio frequency interference (RFI) detector which operates at 800, 1420, and 1665 MHz. Schools and students will borrow the detectors and measure RFI in their communities, reporting their data to an NRAO database. In FY2005 Quiet Skies will hold a summer workshop to introduce K–12 teachers to radio astronomy and RFI using the 40-foot Telescope and the Quiet Skies detector.

Another week-long NRAO/NASA teacher workshop program, funded by the Sun-Earth Connection Division at Goddard Space Flight Center, will return to Green Bank in summer 2005 for K–12 teachers.

NRAO-Socorro will provide credit hours of directed study to students in the Master of Science Teaching degree program at New Mexico Tech. These directed studies will focus on National Standards-based lesson plans for teacher use before and after class visits to the Very Large Array. The FY2005 focus will be on community college and high school physics classes.

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Overview

The responsibility and authority to manage the Observatory is delegated by Associated Universities, Inc. (AUI) to the NRAO Director, Dr. K. Y. Lo, who reports to the President of AUI. Each of the NRAO functional units within the Observatory is led by a senior manager, all of whom work under the supervision of the Director or the Deputy Director, Dr. James Condon.

The NRAO is organized as “one Observatory,” i.e., as a single Observatory with a central management and centralized functional authority for those activities that contribute to the effectiveness of all Observatory endeavors. Despite the geographic separation of the operating sites, priorities for the NRAO programs are established via vigorous discussion across the entire Observatory.

The Director’s Office, located in the NRAO building at Edgemont Road (Stone Hall) on the University of Virginia campus, is the focal point for Observatory management. The Director and the Observatory’s senior management staff regularly seek advice and guidance from the astronomical community through an active and involved set of external advisory committees that includes, for example, the Users Committee, the EVLA Advisory Committee, the Program Advisory Committee, the ALMA Scientific Advisory Committee (ASAC), and ad hoc committees that advise the Observatory on instrumentation and policies. Oral and written inputs received from these committees are accorded high priority by the Director and the Observatory. These committees, and others, provide inputs that are vital to the generation of the NRAO strategy and priorities, both within individual sites (i.e., VLA/VLBA, GBT) and across the Observatory. The Observatory also seeks frequent communication and contact with the astronomical community-at-large through the participation of NRAO scientific, management, and outreach staff in conferences such as the semi-annual American Astronomical Society meetings. Through its attendance at such meetings, the NRAO actively supports its users, promotes radio astronomy’s immense discovery space, and works towards increasing the numbers of radio astronomers and Observatory users.

Excellent communication within the Observatory is vital to its effective management. The Director has instituted several initiatives that will continue into FY2005 and provide for improved communication throughout the Observatory. A regular, high priority, well-organized, and efficiently executed series of senior management meetings has been instituted, for example, to form the foundation of improved communication within the Observatory.

A core, six-person senior management team composed of the Director, Deputy Director, Human Resources Manager, ALMA Project Manager, Head of the Program Office, and the Assistant to the Director meets weekly in Charlottesville for a high-level review and discussion of Observatory programs, priorities, issues, policies, personnel, and future directions. These meetings are nominally an hour in length, with invitees joining the meeting by teleconference when they are on travel.

A larger, twelve-person team of senior NRAO managers—the “Executive AD group”—meets for an hour via videoconference at least twice per month. This team includes the core senior management team, the senior managers responsible for EVLA, the Assistant Directors for Green Bank and New Mexico operations, the senior managers responsible for Business Services, Human Resources, Science and Academic Affairs, and the North American ALMA Science Center. The Executive AD group considers and debates a wide range of sensitive policy, programmatic, priority, and personnel issues in a forum led by the Director.

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To provide a basis for discussion and to maximize the effectiveness of the face-to-face meeting, each senior manager generates a written briefing that is electronically distributed to all attendees prior to the meeting. This material communicates recent news, identifies technical, scientific, and managerial issues, and assesses the status of critical programmatic and policy milestones. The Executive AD meeting inputs are distilled by the Assistant to the Director into monthly informational e-mails that are electronically distributed to all NRAO employees, AUI executives, and key NSF – AST program managers.

Since the Executive AD group includes the Director’s senior management team and broadly represents the Observatory’s facilities and organization, it is the forum that is best suited to debating and setting NRAO’s short- and long-term strategic plans, and priorities. The Executive AD group is further responsible for the complex decision-making that translates NRAO’s strategic plans and vision into well- managed, scientifically productive astronomical research facilities which efficiently serve the professional astronomical community. This translation demands that the Executive AD group decide Observatory- wide scientific, technical, and managerial priorities only after carefully considering their implications for the entire domain of NRAO programs, projects, operations, and users.

To further ensure that all NRAO mid-level managers are well-informed regarding Observatory programs and policies, and that information is transmitted across all geographic sites and expeditiously propagated throughout the organization, a Division Heads meeting is convened via videoconference on the fourth Thursday of each month. This meeting’s invitee list includes the Executive AD group and every employee who functions as a Division Head or its equivalent. Thus, in addition to the twelve members of the Executive AD group, the Division Heads meeting includes mid-level managers from around the Observatory: ten personnel based in Green Bank, nine personnel based in Socorro, ten ALMA personnel from around the NRAO, and six (6) personnel based in Charlottesville. Given its size and different function, the Division Heads meeting has a standard agenda comprised of project and program status reports from all aspects of the NRAO operations.

The Division of Science and Academic Affairs (DSAA) was created in 2003 to address the interests and concerns of the scientific staff. The DSAA recently completed a new Scientific Staff Policy document which describes two parallel tracks for advancement leading to tenure or continuing appointments. It specifies the research opportunities and Observatory responsibilities corresponding to all levels on both tracks. This should improve morale and reduce the stress that had been caused by uncertainties among junior staff members concerning the amounts of time which they could devote to their own research and the standards by which their performance is evaluated. The Director has also instituted a more regular schedule for meeting with the scientific staff as a group, and he expects to have more time for personal interaction with individual scientists as the complete NRAO management team becomes established.

Strict accounting and management of all NRAO activities—operations and construction—is made possible by the comprehensive Observatory Work Breakdown Structure (WBS), a critical management tool. The WBS is a hierarchical decomposition of all NRAO tasks into their component parts. The WBS presents task components in successive levels of detail that combine to accurately describe each activity’s entire scope. By structuring the Observatory’s accounting structure and personnel assignment based on the defined WBS elements, costs and effort can be properly and routinely reported. The WBS is a very powerful management tool for the NRAO.

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The NRAO WBS mirrors the Observatory organization chart. All Observatory activities, including the ALMA and EVLA construction projects, are incorporated into the WBS. Basing Observatory activities on the WBS provides the institutional framework necessary for the Observatory to take on new tasks or modify existing tasks in a straightforward manner while maintaining full accountability.

Program Office

In February 2003 the AUI Management Review Panel stated that the “NRAO is exceptionally strong as the result of a three-year deliberate process of institutional transformation and improvement” and “Furthermore, we find that this process of management improvement is ongoing and has much promise for the future.” At the start of fiscal year 2004, the Observatory continued this management transformation by creating the NRAO Program Office, a new department within the Observatory Management Division. This office began operating in November 2003 with the mission to:

“Define and execute Program Office initiatives to establish the NRAO as a Program Management driven organization that initiates and completes programs on time and within budget while meeting the strategic goals of the Observatory.”

The fundamental role of the Program Office is to perform periodic Program Management Assessments across all Observatory Programs. The objective of these assessments is to evaluate cost, schedule, and critical path against the program’s planned budget and schedule so that early detection of variances that exceed acceptable thresholds permits management to minimize cost and schedule impact by implementing timely mitigation strategies. A program’s ability to produce appropriate metrics for these assessments is dependent on the Observatory’s Program, Project, and Portfolio management maturity. The framework for the NRAO’s Project Management Maturity is shown in Figure 11.1.

This framework is also consistent with the Project Management Institute’s (PMI) Organizational Project Management Maturity Model (OPM3). At each maturity level there is an intersection of the management processes and associated best practices that must be in place under the domains of Project, Program, and Portfolio Management.

The guiding document of the Program Office is the Program Management Plan. This plan defines four Program Office initiatives with specific, measurable objectives and deliverables to achieve stepwise maturity of Observatory business systems and program management functions. These initiatives are executed in parallel and include:

1. Web Based Business Services (WBBS). 2. NRAO Program Management Control System (PMCS). 3. Program Standards and Processes (PSP). 4. Program Management Assessments (PMA).

The Observatory must have in place the appropriate foundation (the Infrastructure and Resources blocks in the Maturity Model) to achieve the higher levels of maturity defined in the model. The initial and primary focus of the Program Office is therefore to define and launch initiatives to create the Observatory foundation for executing effective program assessments. The Program Office Initiatives for Web Based Business Services and the NRAO Program Management Control System and the subsequent integration of these two systems will build the appropriate infrastructure. The PSP initiative completes the foundation

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by institutionalizing project and program management standards and processes. The PMA initiative begins the Program Office assessment of Observatory projects and programs with incremental increases in the level of metrics and reporting as the other initiatives mature.

Figure 11.1: NRAO Project Management Maturity Model.

FY2005 Objectives Overview

FY2004 was characterized by Program Office planning and vendor evaluations. FY2005 will be characterized by the implementation of these plans. Figure 11.2 depicts the document hierarchy and execution roadmap for the Program Office. The controlling, key documents are the Program Management Plan, the Program Office Budget, and the Program Office Master schedule. For each initiative, the Program Office has specified the critical documents for defining, implementing, and deploying the initiative.

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A Program Office Initiatives Working Group, composed of over 50 key stakeholders across all divisions of the Observatory, has been established to ensure the success of the WBBS, PMCS, PSP, and PMA initiatives. This group will have active participation during the complete lifecycle of each initiative including: design, implementation, deployment, training, operations, and maintenance.

As new systems and improved workflows are deployed, training becomes paramount to the organization’s effectiveness in executing these initiatives. A comprehensive approach to training is therefore a key objective of the Initiatives Working Group. Extensive training will be provided to the entire Observatory organization by the Program Office.

Figure 11.2: Program Office Execution Roadmap.

WBBS Initiative Overview

The objective of Web Based Business Services is to host all NRAO business services and associated applications on a common architecture consisting of browser-based clients accessing server applications and backend SQL server databases. The new architecture shall offer the following benefits to the NRAO:

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• Consolidation of data. • Optimize business services hardware and software. • Eliminate need for home grown “specialized tools.” • Reduction of human intervention (copying and moving data). • Eliminate multiple data entry. • Automation of processes & reporting. Figure 11.3 shows the decomposition for the eight major business services of the Observatory.

Business Services System

Property Financial Human Employee Self Travel Procurement Payroll Team Management Management Resources Services Business Business Business Calendaring Business Business Business Business Service Service Service Business Service Service Service Service Service Figure 11.3 - WBBS system decomposition for the eight major business service areas.

Each service consists of one or more subsystems, features, and functions. For example, the Financial Management Business Service is composed of the following subsystems: General Ledger, Accounts Receivable, Accounts Payable, Cash Receipts, Petty Cash, Pay Orders, etc. Further analysis has identified that, within the eight major business-services areas defined above, 59 significant business-services functions require upgrade.

WBBS Objectives for FY2005

The primary focus of the WBBS initiative in FY2005 is to modernize the management, financial, and administrative services and functions of the Observatory. After a diligent review of vendor products, Peoplesoft’s Enterprise One was selected as the core software platform to host WBBS services. The implementation schedule for these services is shown in Table 1. All services, with the exception of Employee Self Services, Fiscal, and Team Calendaring are planned for completion in FY2005.

Table 11.1 - WBBS Service Implementation Schedule Service Complete Procurement FY05-Q2 Travel FY05-Q3 Payroll FY05-Q4 Human Resources FY05-Q4 Property Management FY05-Q3 Employee Self Services FY06-Q1 Fiscal FY06-Q1 Team Calendaring FY06-Q2

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PMCS Initiative Overview

The objective of the NRAO Program Management Control System is to implement an enterprise-level project management system that supports a common scheduling engine, browser-based clients for accessing project data, and integration of budget and actual cost from the NRAO Accounting System with PMCS schedules. The PMCS supports a variety of users including Program, Project, and Control Account managers responsible for project success; Technical and Management members of each project team; and the Schedulers and Cost Analysts who develop and maintain schedule, budget, and cost in the PMCS as directed by management. Salient features of the NRAO PMCS include:

• Interfaces directly to Web-Based Business Services. • Program schedule support for NRAO projects and programs including: construction, development, operations, etc. • Critical path management. • Common metrics (common dashboards, metrics detail). • Integrated cost and schedule management based on earned value project management.

As depicted in Figure 11.4, the NRAO Common Standards and Processes define how the PMCS should be configured to produce standardized reports and metrics across the NRAO user base. All Observatory projects and programs will migrate to PMCS-based Cost and Schedule systems.

NRAO PMCS USER BASE

ALMA GBT

EVLA EVLA-II

Common Standards & Common Reports & Processes Metrics

VLA VLBA

Other NRAO Projects and Programs

WelCom Solution Microsoft Solution

Figure 11.4 – The NRAO PMCS User Base utilizes common standards and metrics.

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PMCS Objectives for FY2005

The PMCS initiative involves the acquisition, implementation, and operation of a web based enterprise- level solution for the capture and reporting of program and project metrics for budget, cost and schedule. The PMCS implementation across all Observatory programs will meet the criteria defined by the Program Standards and Processes initiative and satisfy the reporting requirements for performing Program Management Assessments. The initial programs to utilize a PMCS solution at a standardized level of maturity for cost and schedule metrics in FY2005 include ALMA, EVLA, and the Precision Telescope Control System (PTCS). All NRAO projects and programs will begin utilizing the PMCS solution after the initial programs successfully complete testing.

PSP Initiative Overview

The initiative for Program Standards and Processes institutionalizes the methodology, processes, reporting, metrics, and standards for measurement and management of NRAO projects and programs. Examples of these standards and processes include:

• WBS Change Control Process. • NRAO Standards for Reporting Mechanisms, Formats, and Metrics. • NRAO-tailored PM process definitions based on the Project Management Book of Knowledge (PMI Standard for PM best practices). • NRAO-tailored definition of OPM3 for PM Maturity Levels (PMI Organizational Maturity Model). • Risk Management Process. • Subcontractor Management Process, etc. • NRAO tailored definition of the Earned Value Program Management (ANSI / EIA 748 Standard)

The PSP initiative also includes the ownership and management of the NRAO WBS. The NRAO WBS defines the scope of work across the Observatory and ensures appropriate control points for reporting cost and schedule status to the management team. An active WBS Change Control Process will govern additions and changes to the WBS to ensure the management control points are sustained. Figure 11.5 illustrates the role of the Program Standards and Process Initiative.

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Figure 11.5: Role of PSP Standards and Processes Initiative.

PSP Objectives for FY2005

The PSP Initiative defines the processes, standards, and metrics to be institutionalized across the Observatory. The PSP also involves the normalization of the Observatory-wide WBS which will standardize control accounts and other WBS levels for incorporation into the NRAO financial system. These changes will also enhance the capability for automating cost and budget data between the financial system and PMCS systems. For FY2005 all programs and projects will conform to the new WBS structure.

At the end of FY2004 a set of program reporting metrics for the standardized level of program management maturity was under formal inspection by various NRAO programs. These metrics will provide the basis to begin formal program assessments in FY2005.

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PMA Initiative Overview

The initiative for Program Management Assessment defines the approach for the assessment of NRAO projects, programs, and the Observatory-wide project portfolio. This initiative defines the key role of the NRAO Program Office: perform periodic assessments using standardized reports and metrics that will provide early warning triggers to take corrective action. The PMA will be developed using an incremental, phased approach to maximize assessment capability consistent with the other Program Office initiatives. This approach will be defined in the PMA Implementation plan that consists of the phases shown in Figure 11.6.

Program Management Assessment Phases

Perform Monthly Assessments of PMA Projects and Programs using Metrics Start and Processes at

PHASE I Standardized Level of Maturity

Go to Next Phase when Metrics and Processes are Defined for Next Level of Maturity

Perform Monthly Assessments of PMA Next Projects and Programs using Metrics Phase and Processes at

PHASE II Measured Level of Maturity

Go to Next Phase when Metrics and Processes are Defined for Next Level of Maturity

Perform Monthly Assessments of PMA Projects and Programs using Metrics Next Phase and Processes at Controlled Level of Maturity PHASE III PHASE

Go to Next Phase when Metrics and Processes are Defined for Next Level of Maturity

Perform Monthly Assessments of Projects and Programs using Metrics PMA and Processes at Next Phase Continuous Improvement Level of

PHASE IV PHASE Maturity

Figure 11.6: PMA implementation phases.

PMA Objectives for FY2005

The PMA Initiative involves the active participation of the Program Office in the review and analysis of all NRAO programs. In FY2005 Q1 the Program Office will begin monthly reviews of ALMA, EVLA, and PTCS. Standardized metrics will be captured by these programs and presented in Program Review format. Additional NRAO projects and programs will begin monthly reviews in subsequent quarters of FY2005.

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Business Services

Comprised of Fiscal, Procurement, Budgets, and Grants Administration, Observatory Business Services (OBS) provides the underlying business support for ongoing operations across the NRAO. The services include payroll, receivables/payables, travel processing, budget development, purchasing, and contracts management. During this fiscal year, several key initiatives will be undertaken to improve the level of responsiveness and support to the Observatory associated with the increased needs of the ALMA and EVLA construction projects and the emergence of ALMA operations in Chile and the North American ALMA Science Center in Charlottesville. Most of the initiatives are tied directly to the Program Office Observatory-wide web-based business services (WBBS) effort. The WBBS, funded through the Program Office, will bring about an entirely new Business Services level of support through the use of an Internet web portal.

In general, OBS will expand its reach and responsiveness through the use of an integrated systems approach built upon a common data base and standardized work-flow processes that are being used throughout a variety of organizations worldwide. By increasing the reliance on electronic document processing, OBS will be able to more consistently manage the reporting and projecting of budgets, identify areas needing special attention, and redeploy its employees to other tasks that require their skills rather than have to add staff. The WBBS will facilitate the shift of OBS from labor-intensive data generation and entry processes into a more automated data collection, review, and management reporting environment. To achieve this new operating environment, many functional-area changes will be undertaken. The specific changes are addressed by functional areas below.

Fiscal

Four Fiscal functions are tentatively scheduled to be transitioned to electronic processing during FY2005: travel-expense filing, property management, payroll, and time & attendance. The bar-code system under test at Socorro will also be considered for inclusion with the property-management module implementation. Upon completion of these implementations, the Fiscal Department will be better situated to reallocate its resources to provide expanded coverage of the full breadth of fiscal functions.

Business Services

With the implementation of the time-and-attendance system, the budget-forecasting and full-time- equivalent tracking processes will be greatly enhanced in projecting year-end financial positions and in contingency planning. During FY2005 Business Services will expand non-programmatic funding management and administrative support and will support the establishment of a comprehensive import/export program.

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Procurement

The ALMA and EVLA projects have brought about a significant increase in procurement activity for the Contracts and Procurement Division. To address this increased workload, on-line requisitioning is scheduled to be the first module to be implemented under the WBBS effort. Through this module, materials and services will be purchased and tracked with a much greater level of detail and responsiveness to the end users. The on-line requisitioning system will provide users and managers with reporting and tracking tools not previously available without direct intervention by procurement employees. To further enhance the reporting, tracking, and management capabilities of credit-card purchasing, Procurement is exploring the options to adopt a global procurement card that will be compatible with the on-line requisitioning module. This capability will provide near real-time data about credit-card use, track purchases by vendor as well as the nature of the purchase, and facilitate fraud control through the restriction of authorized purchases.

As foreign operations and collaboration continue to increase, the implementation of a comprehensive import/export process will be accomplished. Key personnel will receive training and guidance in the legal and practical matters associated with moving equipment to and from non-U.S. sites in support of ALMA, EVLA, and other projects.

Fiscal Year 2005 will be a transformational year for the Observatory Business Services in its ability to provide the level of support necessary for the continued growth and effective operation of the Observatory.

Environment, Safety, and Security Overview

The NRAO is committed to excellence in the areas of environment, safety, and security (ES&S). This commitment is an essential part of our mission. Creative and cost-effective ES&S solutions are necessary for our long-term success. Meeting this commitment is a responsibility shared by everyone, including contractors and third parties. The mission of the ES&S Division is to provide guidance and establish policies for protection of the environment, and to support a safe and secure workplace for our staff and visitors.

Environmental Protection

Environmental protection is a key organizational responsibility and a sound business practice. The NRAO is committed to being a positive and creative force in the protection and enhancement of the environment through its research and administrative operations. Recognizing that some activities may have impacts to the environment, all employees have the responsibility to act consistently with environmental principles and objectives.

In the coming year ES&S will continue efforts to identify waste materials to ensure appropriate waste- stream processing. The increased usage of environmentally friendly ‘green’ products will be pursued with facilities. The recording of generator air emissions and releases will be monitored for appropriate emission inventory calculations. In some of our geographical areas air permits are required, and ES&S will provide oversight to ensure proper permitting is achieved. ES&S will pursue the reduction and

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prevention of waste and emissions/releases at all operations. In addition, ES&S will monitor purchases of hazardous materials to ensure that the appropriate handling and disposal alternatives are selected.

Within the EVLA project, ES&S will become more involved with the site-selection process and will work to complete the requisite Environmental Impact Studies to allow the acquisition of environmentally clean site locations. In addition, it is anticipated that some level of support will be provided to the ALMA project to ensure that the terms of the completed Environmental Impact Statement are followed.

Safety in the Workplace

It is the prime responsibility of the NRAO to provide a safe working condition for every employee. The nature and diversity of the Observatory presents unique situations not normally encountered in typical workplace environments. It is the policy and primary concern of the NRAO to take all reasonable precautions to protect the health and safety of employees and of members of the public and to minimize danger from all identified hazards to life and property. The NRAO will comply with all health, safety, and fire-protection regulations and requirements of the various jurisdictions to which they are subject. At the NRAO, safety shall take precedence over more expedient unsafe operations. The NRAO will make every attempt to provide equipment and create conditions to make for a safe workplace.

In the coming year ES&S will strive for the goal of no accidents, injuries, or unsafe work practices or conditions. To aid in achieving this goal, ES&S will develop safety management programs for laser programs, crane and hoist operation, and will develop vehicle safety guidance for all employees. Education and awareness efforts will be provided to employees to ensure that the proper hazard identification processes and safe operations are maintained. In addition, ES&S will sponsor and provide supervisory safety education to managers and lead persons. The NRAO will proactively assure that employees are adequately trained and educated on ES&S issues. NRAO will limit occupational injures and illnesses by emphasizing safety education and safe work practices for all employees.

Emergency preparedness is a vital function and is the responsibility of management and supervision at all levels. Together with the Observatory Business Office, ES&S will finalize the NRAO Business Continuity Plan and conduct a test of the plan to identify weaknesses in the system. The purpose of the Business Continuity Plan is to ensure the resources and procedures are in place to restore the activities of the NRAO with a minimum of down time should an unexpected disruption of services occur.

The development of a Business Continuity Plan is an essential derivative of the security plan. The Business Continuity Plan addresses issues such as infrastructure, data recovery, essential personnel, and resources. The effectiveness of each site’s emergency response needs to be tested, documented, and reviewed. Consideration needs to be given to the internal and external resources necessary to assist the organization.

ES&S will strive to provide appropriate and timely information about ES&S commitments, responsibilities, and achievements to its employees and the public, and will participate in appropriate industry-sponsored ES&S initiatives and programs.

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Secure Facilities

Security of the NRAO facilities is essential to maintain a safe and secure work environment conducive to the professional and personal growth of staff and visitors. The NRAO is committed to protect our staff and visitors and preserve personal and government property from damage or loss. The responsibility for developing and maintaining a safe, secure, and welcoming environment belongs to all employees. In this context, ES&S will strive to support the needs of the individual as well as the NRAO.

In the coming year ES&S will provide educational services in the areas of personal security and workplace safety. In the efforts to protect government assets, ES&S will work toward a policy on the use and distribution of access cards for a secure access control. In addition, ES&S will provide comment and policy assistance in the review and update of NRAO policy manuals to ensure security issues are adequately incorporated into the NRAO guidance documents. ES&S will also continue the development of remote monitoring of common areas at our facilities. Lastly, in conjunction with Observatory Business Services, ES&S will work to assure the physical security of critical business servers and system backups.

Conclusions

The NRAO will continue to be an example in environmental protection and to reduce the number and severity of accidents at our facilities. The Observatory will also continue to identify methods to improve the security of our facilities in non-invasive ways. To accomplish these objectives, the training of our staff is critical to our long-term success. With the support of local and senior Observatory management, the ES&S Division will continue to provide guidance for protection of the environment, and support a safe and secure workplace for our staff and visitors.

Human Resources

Overview

The Human Resources Division, in partnership with NRAO management, ensures a qualified, diverse, and highly motivated workforce focused on achieving the strategic goals of the Observatory through the development of cost-effective and results-oriented human resource programs, policies, and practices. The goals for the division are:

Create an environment that permits the Observatory to attract and retain a highly skilled, productive, diverse, and efficient workforce. Develop, implement, and administer policies and procedures that ensure fair and lawful treatment of employees. Provide management with quality and timely services, information, and advice to support planning and decision making. Develop, implement, and administer HR programs that enhance retention and maximize productivity and effectiveness of employees.

To meet the increasing demands on the division due to the inclusion of the ALMA Observatory in Chile and the EVLA construction project, the division will focus over the next several years on defining methods to streamline the work of a small human-resources staff.

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Human Resources Information System

The Human Resources Information System (HRIS) provides the resource to meet the Observatory’s informational needs. Current demands for vital personnel data are required from every conceivable customer. These demands range from management reports of personnel count and labor allocation, to requests from funding sources, to compliance reporting and benefit support.

The Human Resources division intends to replace the current legacy HRIS database in FY2005 in conjunction with other Observatory management divisions. Human Resources will identify a fully integrated database system that will allow for management, supervisor, and employee self-service access to appropriate HR data through a secure web portal.

Employment

Employment services at the Observatory are a hybrid of several types of employment environments: research, academia, production, and service industries. The Observatory’s ability to attract skilled and experienced personnel to rural settings is always a challenge. The construction of the ALMA Observatory in the mountains of Chile, South America compounds the problem.

Special emphasis in FY2005 will be given to the ALMA Observatory Human Resources function. A number of major tasks must be undertaken to establish a Chilean Human Resources structure that will incorporate the legal requirements and employee needs of the Chilean operation and at the same time satisfy the requirements of the NRAO and ESO.

Recruitment

The division focuses on the technical competencies required to fill each job. Once established, the job opening is placed in one or more public venues. These consist of scientific and technical journals and related employment web pages, nationally available web-based employment services, and the Observatory’s own employment web page. Utilization of temporary employee service providers has increased and this trend is expected to continue in FY2005 with the dual benefit of providing the much- needed short-term workforce through the final U.S.-based phase of the ALMA construction project and reducing the need for downsizing at the end of the project.

Compensation and Benefits

FY2004 marked the culmination of a four-year compensation modernization plan. The division, with the assistance of a prominent compensation consultant, reviewed and updated the salary and wage system with the primary goal of returning the Observatory to a competitive level within the scientific research field, and secondly ensuring that all employees’ jobs are properly benchmarked and compensated. In FY2005 the division, with our compensation consultant, will review market-sensitive jobs to ensure the Observatory maintains a competitive compensation program which is crucial to the recruitment and retention of vital staff.

The benefits plans of the Observatory continue to be a strong retention tool in a time of tight budgets. The division continually monitors the cost of existing plans and will research current trends in employer- sponsored benefits. During FY2005 the focus will be directed to the identification of benefit

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enhancements that can be offered through the Observatory as voluntary employee-paid programs such as life insurance with portability after retirement and long-term-care insurance.

Diversity

Astronomy by nature is a multi-national and multi-cultural endeavor. The Observatory has a strong record of promoting employment and services to a diverse work force. In FY2004 the Human Resources division coordinated an exhibit at the annual conference of the Society of American Chicanos and Native Americans in Science (SACNAS).

In the coming year the division will coordinate the Observatory presence at two professional minority or female conferences to promote employment and educational opportunities. The Human Resources division has taken the lead in the formation of an ad hoc Committee on Diversity with members from across the Observatory with the objective of increasing the representation of women and minorities in professional and managerial positions.

The Observatory annually prepares an Affirmative Action Plan. The purpose of this plan is to establish goals and monitor performance in the hiring and promotion of underrepresented classes. Due to the fact the Observatory operates in a number of geographical areas that affect the availability statistics, the overall plan is composed of sub-plans for the major sites Charlottesville, Va., Green Bank, W.V., and Socorro, N.M.

On an Observatory-wide basis, as measured in the FY04 Plan, the NRAO achieved its goals in new hire or promotion of minorities or females in a significant number of predefined Job Groups when compared to internal and external availability; those groups include: Mid-level Management (female and minority), Senior-level professional (female), Entry-level professional (minority), Monthly technical (minority) and Weekly technical (female).

In FY05 the Observatory has as its goal to hire and/or promote at the availability rate in those job groups where it has been determined that NRAO has an under-representation of females or minorities as calculated in the FY2005 Affirmative Action Plan.

Non-Immigration Visas

As with most research institutes, the Observatory has been severely impacted by the recent national and international security concerns raised by the national tragedy of 2001. The process of filing and maintaining non-immigration visas is no longer a small administrative task but has become a significant focus of time and effort. The Observatory continues work with ever-changing Federal requirements in the Exchange Visitor and Non-immigrant work-visa application and processing regulations.

Training and Development

FY2004 saw the introduction of an Observatory-wide Management Training Program with the focus on developing managerial and leadership skills. The training program, a collaboration of the Human Resources division and University of New Mexico’s Professional Development Center, provided a five- day training experience for two dozen division-level managers. At the conclusion of the training these managers encouraged the Observatory to offer a similar program to first-line managers. In FY2005 the first group of first-line managers will be enrolled in this training program.

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ALMA/Chilean HR Policy

Presently the number of ALMA/NRAO employees stationed permanently in Chile remains small. However, FY2004 has seen a three-fold increase in the number of such employees. As the project construction continues to ramp up and as the ALMA Observatory becomes a reality, there will be the need for a complete Chilean human-resources structure. This year the Human Resources division has developed hiring procedures for three types of employees: those hired by the Executives, international hires, and ALMA local Chilean hires. The focus for the Human Resources division in FY2005 will be to design policies and procedures that comply with the needs of each of the Executives and the Chilean labor system.

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New Initiatives

In fulfilling its mission of designing, building, and operating large radio astronomical facilities, the NRAO plays a major leadership role in the global radio astronomical community. Typically, many years are required to define and develop a major new facility, so that it is appropriate to devote a small fraction of our resources to long term planning of facilities and instrumentation whose construction is not yet funded or even well defined.

Members of the NRAO staff are currently involved with a number of such new initiatives: the international Square Kilometer Array (SKA) project; the Long Wavelength Array (LWA); the Frequency Agile Solar Radio Telescope (FASR), the extension of VLBA baselines to space; the development of Focal Plane Arrays; and the characterization and mitigation of radio frequency interference.

The long term role of AUI/NRAO in these projects is not yet defined. It may be as a partner, as a member of a consortium or other collaborations, or as the leader. But, whatever our ultimate role, continued participation in these long term initiatives maintains and strengthens our leadership role, while at the same time enhances our ties with and fosters the health of the broader radio astronomy community. In addition, as a key source of both technical and scientific expertise, the NRAO serves as a valuable resource to the world-wide astronomy community for both ground-based and space-based initiatives. Conversely, participation in these broadly based initiatives benefits the NRAO to the extent that it enables the Observatory to keep pace with and exploit technological innovation.

The Square Kilometer Array (SKA)

In recent years there has been increasing discussion within the international radio astronomy community of the need to develop a radio telescope having up to two orders of magnitude improved sensitivity compared with existing instruments. Because current receivers are close to their theoretical limits, the only way to achieve significant improvement in sensitivity is to greatly increase the collecting area. However, any simple extension of conventional approaches to obtaining large collecting area are prohibitively costly, hence the need to break the cost curve to achieve a collecting area equivalent to one square kilometer. This development project is known as the Square Kilometer Array (SKA). The NRAO is a member of the U.S. SKA Consortium and is represented on the International SKA Steering Committee; these two bodies are charged with the coordination of national and international efforts, respectively, to develop the next generation of radio astronomy instrumentation needed to address the scientific questions of future decades. The NRAO staff have been active in developing the scientific case for the SKA, in addressing the technical challenges presented by the SKA, and in organizing meetings to focus the attention of the U.S. and international radio astronomy community on the opportunities presented by the SKA.

Many of the techniques and instrumentation currently being developed for the EVLA are an important part of the planning for the SKA. This includes wideband low-noise receivers and feeds, an advanced correlator designed to minimize the impact of RFI, the use of broad-band fiber optic transmission systems, configuration optimization, advanced data management and archiving techniques including multiple-field calibration in the presence of non-isoplanatic screens, non co-planar and high dynamic range imaging, the effective use of data archives, and real-time imaging from complex data acquisition. NRAO staff will also continue to work on various aspects of the design as members of the International Engineering Working Group which is charged with coordinating and evaluating the technical approaches

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being developed throughout the international community and as Chairs of the international Systems Engineering Signal Processing, Software, and Operations Working Groups.

The basic concept and the location of the SKA are still very uncertain. However, it is becoming increasingly clear that a single design cannot provide the wide frequency range desired, especially if the SKA has multiple beams covering a wide field of view or is electronically steerable. Although the EVLA will provide a major improvement in sensitivity and resolution over currently available instruments at centimeter and decimeter wavelengths, it will have only limited capability below 1.2 GHz. An SKA operating from a few hundred MHz to 1.5 GHz located on a radio quiet site in Western Australia is an attractive possibility to the U.S. user community and might be technically feasible if promising developments in Aperture Array technology in Europe materialize.

The Long Wavelength Array (LWA)

Perhaps the last frontier in the electromagnetic spectrum lies at long radio wavelengths, where radio astronomy first began with the work of Karl Jansky some 70 years ago. Although the relatively poor resolution at meter and decameter wavelengths and the effects of ionospheric distortion have, until recently, precluded much attention to this part of the spectrum, wide-field diffraction limited imaging at arcsecond resolution is now feasible. Over the past decade 74 MHz (4 meter) receivers and feeds provided by the Naval Research Laboratory (NRL) have been installed on the VLA and have been used by many observers. But, the NRL system is limited to a single frequency, can only be used for strong sources, has limited dynamic range, and the resolution is limited to 10-20 arcseconds, so there is growing interest in a dedicated array operating at meter and decameter wavelengths.

The Long Wavelength Array (LWA) is an ambitious plan for an array of 50 to 100 stations spread over 400 km in New Mexico with a central condensation near the VLA. The LWA will operate in the frequency range 10-90 MHz, where it will have a variety of astronomical, solar, and ionospheric applications. The LWA is a joint venture of the Southwest Consortium (SWC) and the Naval Research Laboratory, and has received endorsement by the recent NAS Decade Survey Committee. The first phase of the project, using NRL funding, will be to build two prototype LWA stations to be used for astronomical research at 74 MHz together with the existing system on the VLA antennas and using the VLA correlator. Discussions between NRAO and the SWC are underway to allow the SWC to implement this plan and to define NRAO’s role. Meanwhile, NRAO staff is continuing its involvement with the design of the array and a staged process of development.

The Frequency Agile Solar Radio Telescope (FASR)

The Frequency Agile Solar Radio telescope project is an initiative of the solar-physics community to build an optimally designed instrument to perform broadband imaging spectroscopy over a frequency range of ~0.1-30 GHz. The project was ranked as the number one small project (<$250M) by the decadal review of the Solar and Space Physics Survey Committee of the NAS/NRC Space Science Board. The project has also been endorsed by the decadal review of the NAS/NRC Astronomy and Astrophysics Survey Committee as one of three solar projects for the coming decade: the Advanced Technology Solar Telescope (optical/IR), the Frequency Agile Solar Radiotelescope (radio), and the Solar Dynamics Observatory (optical/EUV/SXR).

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FASR will probe the solar atmosphere from the chromosphere up to the middle corona. It is designed to address an ambitious science program, including coronal magnetography, the physics of flares, drivers of space weather, and the thermal structure and dynamics of the solar chromosphere. FASR will bring unique capabilities to bear on these problems, capabilities that are highly complementary to existing and planned ground- and space-based facilities.

NRAO staff members are playing a leading role in preparing a proposal to the NSF for the design, construction, and operation of FASR. A proposal is being prepared which will be submitted to the Atmospheric Division of the Geosciences Directorate for the FASR Design and Development Plan (DDP). The FASR DDP will request funding in support of the myriad of activities needed to prepare the proposal to construct and operate the instrument, including specification of FASR science requirements, the technical system block diagram and interface specifications, data flow diagram and software plan, a project Work Breakdown Structure (WBS) and task implementation plan, identification of institutional participants, a detailed project organization and management plan, costing methodology and a cost estimate, and operations planning.

A critical component of the FASR DDP is to organize the constituent partners of the project into a new organization managed by Associated Universities, Inc (AUI). This organization will be responsible for constructing and operating FASR. Participating partners currently include the NRAO, the New Jersey Institute of Technology, U.C. Berkeley, the University of Maryland, and the University of Michigan. Hence, the FASR project under AUI management will include a strong university-based component. A number of foreign partners will also likely participate in the project, notably Paris Observatory, ETH/Zurich, and the Potsdam Astrophysical Institute.

Space VLBI

The angular resolution of the VLBA, which exceeds that of any other imaging instrument in astronomy is limited by its overall size of approximately 8,000 km and the shortest operating wavelength of 3 mm. Further improvement in resolution can only be gained by extending the baselines to space and/or reducing the minimum operating wavelength. Various programs at the Haystack Observatory and in Europe are targeted at extending VLBI techniques to shorter wavelengths, but the effects of tropospheric fluctuations and opacity have so far limited progress.

For more than 25 years, the NRAO has been actively involved in extending interferometer baselines to space and to use space-based facilities to facilitate data transfer. In the 1970's we participated in experiments with the Canadian CTS satellite; in the 1980's NRAO collaborated with a large international group in using the TDRSS satellite to extend VLBI baselines to more than 20,000 km. For more than ten years, with NASA support, we played a major role in the design and operation of the Japanese VLBI Space Observatory Program (VSOP) through the use of the VLBA antennas and correlator, as well as the Green Bank tracking station.

Two missions are under discussion by the international radio astronomy community: VSOP-2, and RadioAstron. VSOP-2 is a Japanese initiative consisting of a single spacecraft, with a 10-m off-axis paraboloid antenna, observing wavelengths from 7 mm (43 GHz) to 6 cm (5 GHz), a data rate of 1 Gbps, and a planned launch early in the next decade. For more than 20 years, Russian scientists at the Astro Space Center have been working on the development RadioAstron, a space VLBI satellite operating at four wavelengths as short as 1.3 cm. Due to the deteriorating economic and political conditions in Russia following the collapse of the Soviet Union, progress has been frustratingly slow. Recently the Russian

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space agency has expressed renewed interest in completing the RadioAstron spacecraft which now has the highest priority for all space-based astrophysics missions in Russia, and plans for a launch in early 2006. However, there are still significant technical and organizational hurdles to be overcome if a 2006 launch is to be realized.

NRAO staff members have been actively involved in the planning for both these international space VLBI missions. At a minimum, we anticipate the use, by the world-wide community, of the VLBA and GBT antennas as ground elements of the earth-space interferometers for both RadioAstron and VSOP-2. In addition, the NRAO has developed considerable expertise in operating satellite earth stations and in correlating the complex data from earth-space interferometers; and the NRAO has several antennas on the Green Bank site that can provide critical support of future space VLBI missions or other astronomical satellite tracking programs, as opportunities arise. However, participation in these exciting opportunities through the operation of ground stations or the correlation of data will depend on substantial support from NASA.

Focal Plane Arrays (FPAs)

There is increasing interest worldwide in replacing the typical single feed-receiver system commonly used at the focal point of large filled aperture radio telescopes with a focal plane array that can synthesize a large number of simultaneous beams and thus greatly increase the observing efficiency. However, there are a number of challenging technical problems that need to be addressed before such systems can come into actual use. These issues fall into two categories: simulations and experimentation. The simulations are needed to further constrain design requirements and to better understand the noise issues. The latter are much more complicated than for single element feeds since the noise from one element can be correlated with that from another. On the experimentation side NRAO would like to collaborate with colleagues in Canada on this and on beamforming aspects of FPAs. We would like to put a fast sampler at the back of several (4 to 8) element ports and beamform in software to ensure that simulations are accurate and that a reasonable noise performance can be obtained. Although the Europeans are putting substantial effort into similar devices, neither is attacking the problems in the ways described above. These projects will be essential for study of FPAs and are also directly on the path to implementing larger production units that can be used on the GBT and other large radio telescopes.

RFI Mitigation Research

The NRAO staff has been conducting collaborative research on RFI mitigation techniques with engineering faculty and students at Brigham Young University and at the University of Virginia. This work has been supported by NSF MRI grant No. 0079162 to NRAO with contracts to UVa and AST grant No. 9987339 to BYU. Successful algorithms have been developed and demonstrated on the GBT for adaptive cancellation of satellite signals near 1612 MHz, radar blanking in the 1250-1300 MHz range, and blanking of pulsed airborne distance measuring equipment signals in the 1025-1150 MHz range. The radar research yielded considerable information on multi-path RFI propagation and a Kalman filter algorithm was developed for tracking variable delay aircraft reflections. All of these techniques have immediate application to high-redshift HI and OH spectral line work at the GBT and EVLA. Thus far, this work has resulted in two refereed papers plus three in preparation, two BYU Masters Theses, a UVa Masters Project, a UVa Senior Thesis, three workshop and conference proceedings papers, and six conference presentations.

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A new, three-year MRI grant (0352705) to the NRAO and BYU has just been funded to begin October 1, 2004 for a continuation of this research. The primary emphasis will be on implementation of successful algorithms in high-speed signal processing hardware, primarily field-programmable gate arrays, to allow the techniques to be used in spectroscopy bandwidths on the order of 100 MHz or more. We will extend the adaptive cancellation research into the UHF range with specific applications to television and personal communications signals. This will increase the spectrum available to HI absorption and OH megamaser observations to even higher redshifts. Our RFI data acquisition and general purpose signal processing and analysis capabilities will continue to be upgraded.

The RFI mitigation research is complementary to the efforts at Green Bank and the VLA to maintain and improve the radio environments at these sites. For example, at the GBT the RFI data acquisition antennas serve the purposes of gathering research data, measuring and diagnosing locally generated RFI, and measuring signals generated by transmitters in the National Radio Quiet Zone. A program to verify and improve the accuracy of radio propagation models used in Quiet Zone administration will be coordinated with RFI research activities in a project underway to install a remotely controlled RFI measurement station at the top of the GBT feed arm.

Charlottesville Facilities

Charlottesville operations are now divided between four buildings on three campuses: (a) Stone Hall, a 24,423 gross sq. ft. building on Edgemont Road built by the University of Virginia to the specifications of the NRAO and leased from the University by NRAO / AUI since 1964; (b) 38,500 gross sq. ft. of commercially-leased space in two buildings located immediately south of Ivy Road on a campus formerly known as the “ITT complex”; and (c) commercially-leased space on Old Ivy Commons (OIC) where parts of ALMA and NRAO Business are housed.

The general contractor performing the Stone Hall construction and renovation work at the NRAO Edgemont Road facilities, Martin/Horn Inc., is making good progress and expects to reach their critical “substantial completion” milestone by mid-December 2004. An NRAO facilities team is managing the construction and planning for the significant transition into the renovated Stone Hall facilities. Full occupancy of Stone Hall is expected by February 2005. The lease on the OIC facility expires February 28, 2005, and the employees who have been located there for the past two years will return to Edgemont Road.

Completion of the Stone Hall renovation work provides the space needed to accommodate the North America ALMA Science Center (NAASC), the focal point for user support and further development of the North American component of ALMA Operations. This addition will also provide for growth of the Library and conference facilities, the renovation and upgrading of the HVAC and communications infrastructure in much of the existing building, and improvements in fire protection and accessibility, providing a safer and more efficient work environment.

To create a more synergistic and collaborative environment for the development and production of the ALMA electronics, the ALMA Tucson group and the Charlottesville Central Development Laboratory (CDL) have been consolidated into one facility: the NRAO Technology Center (NTC). The location of this facility, formerly the ITT complex, is close to the Edgemont Road / Stone Hall facility and therefore close to the NAASC. Its two buildings were substantially modified in FY2004 to accommodate the office

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and lab space needs of the NTC and are now well-suited to the requirements of the ALMA and CDL work being done there. Spectrum Management

Spectrum management duties for the NRAO are carried out by the Charlottesville-based spectrum manager in consultation with the GB and AOC RFI groups which monitor and mitigate RFI to the Observatory's instruments. The spectrum manager is assisted on an oocasional basis by current and retired staff members who have participated in spectrum management and RFI-related activities in the past. The NRAO staff scientists participate as members of IUCAF (http://www.iucaf.org/) and CORF (http://www7.national-academies.org/bpa/committees_corf.html).

Current Activities

The NRAO Office of Spectrum Management was revamped during the recently-completed 2003-2004 program year. The pace of some ongoing activities was quickened and a number of new initiatives were undertaken. An NRAO spectrum management home page is now on-line at http://www.cv.nrao.edu/~hliszt/RFI/RFI.htm, bearing links to all of the NRAO's spectrum management, RFI- and Quiet Zone-related activities. The first two meetings of an ongoing, quarterly, free-to-call-in North America teleconference for RFI concerns were held. An international mailing list ([email protected]) was instituted so that RFI concerns could be quickly and easily disseminated.

At the broadest level, the spectrum manager participated in international activities of the ITU-R as a member of WP7D (radio astronomy), TG1/8 (ultra-wideband), and TG1/9 (compatibility between active and passive services in certain band-pairs). Each of these entails monthly U.S. telecons and semi-annual 5-10 day meetings (mostly) in Geneva. The spectrum manager also attended the annual meeting of CRAF, Europe's analogue to CORF, in at the Observatoire de Paris.

On a national level, NRAO filed 4 comments with the FCC on issues ranging from 14.5 GHz microwave links on ships to redefinition of RFI using an "interference-temperature" metric to use of the tv broadcast bands by unlicensed devices. FCC activities during the past year continued at an astonishing pace. The L-band spectrum was entirely rearranged to accomodate next-generation wireless services, placing the 1720 MHz OH line squarely in the middle of a new band (1710-1755 MHz) dedicated to mobile communications. Rules for administering the National Radio Quiet Zone were streamlined (not to our detriment). New rules were adopted for the 3-4mm bands (with broad allocations to radio astronomy and some catches) and a new web-based system for granting unlicensed 76 GHz microwave links will shortly be brought on-line.

Some matters involve individual NRAO sites and instruments. The Mass. State Police are seeking permission to use helicopter video surveillance over Metropolitan Boston at 4.9 GHz, which may interfere with C-band work at the Hancock, NH VLBA site. NRAO agreed to suspend C-band VLBA observing at Hancock temporarily so as to permit such surveillance during the period of the Democratic National Convention, but the final resolution awaits further discussion. Medical telemetry at a hospital in North Liberty, IA threatens to interfere with VLBA use of the 608-614 MHz band at its nearby station; coordination discussions between VLBA personnel and the hospital's representatives are ongoing. NRAO has MOUs of varying utility concerning WiFi on planes and use of the Iridium system, etc.

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The spectrum manager initiated an outreach effort in an attempt to stand up for passive services in the face of a veritable stampede toward unlicensed use of the spectrum. A stiff letter of protest was written to a Washington DC policy-planning organization which has represented a number of consumer organizations in various FCC filings supporting spectrum de-regulation and wider use of unlicensed devices. This foundation's filings and other policy documents equate spectrum management with suppression of free speech and this argument has unfortunately been embraced by a host of other non- profit organizations dedicated to preserving civil liberties. As part of this outreach effort, the NRAO has formally suggested to the FCC that informational material concerning responsible use of unlicensed devices in sensitive areas be required at the point of sale.

Activities During the New Program Year

Not all major activities during the new Program Year can be specified with much precision. The various threads mentioned above will be continued. A few emerging issues and goals may be cited.

During the coming year, CloudSat will be launched, putting a 2 kW 94 GHz downward-looking pulsed radar into a 705-km polar orbit as part of NASA's A-train: initial coordination meetings between NRAO and JPL have just begun and will be broadened to include the world-wide mm-wave community. The coming year will see an increased push for use of broadband internet connection over power lines (BPL or PLC) which has produced strong RFI in most cases where adequate tests have been performed. Ultrawideband devices instantaneously using the entire spectrum below 10 GHz will be implemented and short-range uwb vehicular radar at 24 GHz will be found on more and more cars. The FCC is proposing a widened spectrum allocation for Iridium, bringing it much closer to the 1612 MHz line. New initiatives for unlicensed use of spectrum will undoubtedly emerge.

Goals for the new year include fostering increased participation in spectrum management activities on the part of mm-wave observatories, which so far have been above the fray (so to speak) but will be involved as RFI issues migrate to higher frequency. NRAO's outreach effort to policy-making organizations, newspapers, and the like will be enhanced.

Another set of goals for the coming year relates to implementation of the ALMA Radio Quiet Zone, which should serve as the model for an emerging class of protected regions. The existence of national radio quiet zones of this sort will, it is hoped, eventually be recognized at the highest level, based on a draft new question submitted by NRAO to WP7D of the ITU-R. A related issue is wider involvement of ALMA in spectrum management issues. As the largest radio observatory and the operator of a radio quiet zone, such involvement is incumbent upon ALMA. A plan for the establishment of an ALMA office of spectrum management within the international project was formally submitted for inclusion in its operations plan. Finally, ALMA and/or NRAO must become involved in CITEL, the inter-american spectrum management group which represents Latin American interests most broadly at the ITU. CITEL is currently dominated by North American commercial interests, not always to the benefit of the passive services and the instruments hosted by various South American nations.

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Introduction

This Program Plan has been written to a Mission Requirement Level (MRL) of $55,000k. The principal elements in the MRL are $1,000k for the first year of preparation for operations of ALMA, the large millimeter array now under construction in Chile; $8,700k for a continuation of the project to expand the VLA, the EVLA, at an accelerated level begun in FY2004; and $45,300k for support of ongoing NRAO operations.

The President's Request Level (PRL) is $47,410k, and includes the initial year of ALMA Operations at $1,000k, funding of the EVLA at the baseline rate of $5,340k, and $41,070k for continuing operations of the existing facilities at NRAO. This level of funding is less than the MRL of $55,000k by $7,590k.

The Need for the Mission Requirement Level

In order to understand the implications of the PRL and the MRL it is helpful to examine some of the principal differences between the Program Plan for FY2004 and the MRL for FY2005.

The Program Plan for FY2004 for NRAO Operations (SPO-1) was based on new funding from the NSF of $54,970k. Included in this amount are funds for the EVLA Project at an accelerated rate of $9,345k, for the replacement of the azimuth track system of the Green Bank Telescope (GBT) of $4,573k, and $41,052k for ongoing operations at NRAO. The Program Plan also incorporated $2,154k of funds which had been conserved in FY2003 and carried forward to minimize the impact of the austere FY2004 budget. All of this carryover is allocated to the support of continuing operations, raising the total budget for continuing operations to $43,206k.

The MRL for FY2005 includes a net growth over the FY2004 budget for continuing operations of approximately $2,047k, arising from increased expenditures of $2,960k offset by reductions achieved during the later part of FY2004 amounting to $913k.

The increased expenditures resulted from several factors, the most significant of which are:

• Change in salaries, including upgrade of professionals and benefits $ 990k

• Increment arising from new personnel $ 416k

• Acceleration of implementation of the Program Office $ 750k

• Augmentation of the Jansky Fellowship $ 254k

• Completion of certain NPF activities $ 400k

• Augmentation of independent research funding $ 150k

Total additional costs, FY2004 to FY2005 $2,960k

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The principal component of the growth is the adjustment made to the salaries and benefits of the Observatory work force. The average increase was 3.6%. In addition, the effort to preferentially raise the salary levels in the technical areas of science, engineering, and computing will be completed in FY2005, with resultant salaries now almost competitive with those at similar institutions.

Three or four new positions will be created in FY2005. The new personnel will fill critical needs in business management and in web services. Other personnel costs include a continuation of the augmented Jansky Fellow program begun in FY2004, and the support of a number of scientists and engineers who had been seconded to Non-Programmatic Funded (NPF) activities in FY2004; examples are the National Virtual Observatory and Spacecraft Tracking.

A second component is the significant increment in both NRAO staff in outside contracts need by the Program Office in FY2005 to implement the several activities described in more detail in Chapter 11. The Observatory recognizes the need to have available to it the modern tools of program management and is moving forward aggressively to deploy these tools. The National Science Foundation is also requesting more detailed reporting, requiring new tools.

A modest increase in the available funding for research instrumentation is planned in an effort to stimulate more research in innovative technology.

It was recognized that the anticipated growth in FY2005 was greater than could be supported even at the Mission Requirement Level, and thus a number of cost-saving measures were introduced in the latter part of FY2004. The two most significant were:

• Reduction of selected personnel positions $648k

• Reduction in Observatory travel $265k

Total Reductions annualized for FY2005 $913k

The Adequacy of the Mission Requirement Level

Beginning in FY2003, the NRAO has been making a concerted effort to conserve funds by eliminating activities which, though useful, did not have high priority in comparison with the demands for operating the observing facilities. As described above, a number of persons left the Observatory and have not been replaced. In addition, spending on materials and on infrastructure has been constrained. Spending on general travel has been reduced by 20%.

As a consequence of these austerity measures the NRAO operations costs have been reduced, but the flexibility to make additional reductions has also been reduced. Moreover, there is great pressure to increase the budget to provide additional strength in program management, especially in view of new reporting requirements such as GPRA. There is pressure to increase funds for infrastructure support, especially in the areas of GBT maintenance, VLA track maintenance, and antenna bearing maintenance for both VLA and VLBA. Finally, the current budget is not adequate to replace the large inventory of computers on a routine and prudent schedule. The detailed lists of currently unfunded projects contained

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in Section 6, NRAO Facilities, and the extensive list of computing needs in Section 9, are evidence that even the MRL is not sufficient to carry out the programs expected at the Observatory.

The Impact of the President’s Request Level

It is obvious that, given the upward pressure on the MRL, funding at the PRL will impose severe hardships on the NRAO and will effect a significant reduction in the level of activity. The following sections give a general overview of the types of reductions which will be necessary. Changes in staffing levels will be an important component, but because the planning of these changes has not been completed and shared with the staff, it is not possible to provide complete details in this document.

The reduction required to achieve the PRL is $7,590k. We have identified a number of elements which combine to meet this target. These are:

• a reduction in the pace of the EVLA construction $3,360k

• a reduction in student programs, general materials, and services $2,119k

• a reduction in Observatory staff levels $ 489k

• relief obtained from uncommitted FY2004 funds $1,622k

Total Reductions $7,590k

Reduce the EVLA Program

Under the PRL, the funding for the EVLA program would be reduced by $3,360k, from $8,700k to $5,340k. Since the overall cost of the project will not be changed, the result of the PRL will be to halt the acceleration of the program which was begun in FY2004. Thus the placing of large production orders of critical components will be curtailed, and the number of antennas which could be outfitted in FY2005 will revert to four, as called out in the original baseline program.

Reduce Student Programs, Materials and Services

There are a number of activities which the Observatory could cancel or defer without an immediate impact on the quality of the observations being undertaken with the telescopes, but which would have a serious negative impact on the Observatory's capabilities in the long run and decrease the vitality of the U.S. radio astronomy community as a whole. Examples are the reduction of the support for students using the GBT; the elimination of funding for student support using the VLA/VLBA; the reduction of the Jansky Fellowship Program designed to stimulate wider interest in the program, thereby attracting to the Observatory post docs of the highest caliber and increasing the number of trained radio astronomers; reduction of programs in Safety, Human Resources, and New Initiatives; extending the service life of computer and network equipment; and a reduction in the amount of infrastructure work (examples: painting the GBT, repairing the VLA railroad track). As noted above, it was intended that in FY2005 the Program Office would implement many of its tools for program management, but money could be saved by deferring the acquisition and implementation of these badly needed tools. Taking these steps could reduce the budget for continuing operations by as much as $2,119k.

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Examples of maintenance activities currently being undertaken which would be reduced are: a deferral of structural inspections of the GBT; the reduction from eight to five in the number of VLA antennas undergoing major preventative maintenance during the year; the canceling of the major maintenance visits to three or four VLBA antennas which would normally be undertaken during the coming year, and the deferment of the purchase of materials needed to implement the improved environmental health and safety programs. The impact of any one of these reductions is difficult to judge in the abstract; as an example, the loss of an antenna bearing would cost the facility the use of that antenna for a significant period of time.

The number of successful observing hours is the most important measure of the Observatory's productivity. However, operating these telescopes is costly in terms of personnel, materials, supplies, utilities, and maintenance and a reduction in the number of operating hours would yield some savings. Therefore, some consideration will have to be given to reducing the amount of observing time scheduled on the VLA, the VLBA, and the GBT. Such a step would be taken only after other austerity measures have been implemented.

Reduction in Observatory Staff Levels

After taking account of funds carried forward from FY2004, there remains a shortfall of about $489k, and it is inevitable that there will need to be a reduction in the number of employees. The details of this reduction have not been worked out, but the level of the reduction which is required can be estimated. A typical employee at the NRAO earns $56k per year, and the benefits reckoned at 32.5% require an additional $18k. However, the typical employee has served the Observatory for fifteen years and is therefore eligible for a severance package which is about 40% of salary, or $22k. Therefore, for each employee who is laid off at the beginning of the fiscal year, there will be a reduction in personnel costs of $52k. To achieve a reduction in the budget of $489k entails laying off approximately 10 employees, or approximately 2% of the workforce who support the continuing operations at NRAO and contributing effort to the EVLA construction.

Elimination of a Program Element

Given that many cost-savings measures have already been implemented during the course of FY2004, it should be asked if the further reductions described above call into question the viability of one or more of the facilities of the Observatory. If this were judged to be the case, then the alternative, the elimination of one of the major program elements, would have to be considered. However, the elimination of any one of the elements would represent a major loss in the capabilities available to the astronomical community, since each makes a unique contribution to that effort. The elements are:

• The Very Large Array is the world's premier radio telescope. It is currently being expanded to augment its capabilities. It can not be closed without also eliminating the EVLA project, which is built on the VLA antennas and infrastructure.

• The project to expand the capabilities of the VLA, the EVLA project. Now in its third year, this project will multiply the scientific capability of the VLA by an order of magnitude. The project was highly recommended in the decadal review, and has been authorized by the Board of the National Science Foundation.

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• In the recently completed survey of the future needs for high angular resolution, a number of important fields of research were identified which are poised for major advances if suitable instrumentation is brought to bear. Examples are astrometry for proper motions and parallax needed to study the dynamics of the solar system as well as detailed understanding of earth rotation and fundamental geodesy; the physics of evolving stars, supernovae, black holes and the formation and evolution of extragalactic jets; and the identification of sources of gravitational radiation. Current astronomical research in these fields would be severely hampered without the unique capability of the VLBA. It is the only dedicated astronomical instrument capable of imaging at milliarcsecond resolution, and is the central element in the facilities described in the plan.

• The GBT is the most advanced radio telescope ever constructed, featuring a huge unblocked aperture, a high-precision active surface, a rotating turret for fast selection of receivers, and state- of-the-art electronics. With the commissioning phase essentially complete, it is being used to address projects ranging from low-frequency radio phenomena such as atomic hydrogen and pulsar emission, to high-frequency molecular line and dust emission. Its unique capabilities have produced a stream of scientific results, such as the discovery of 13 new pulsars in a single beam when searching a globular cluster.

Because of the unique capability each of these facilities brings to forefront research in astrophysics, not only in the United States but elsewhere in the world, we conclude that every effort must be made to preserve them.

It might be asked if one of these major program elements could be suspended for one year, thereby achieving the desired savings but maintaining the possibility of resuming the operation of the facility in FY2006. This is not a practical option. If the operation of one of these units is suspended for one year, the technical staff comprised of outstanding scientists and engineers, and highly-skilled technicians, will be laid off. They will surely seek employment elsewhere, and because of their technical and professional skills will almost surely find work. They will naturally have lost confidence in the Observatory and would be unlikely to return after operations are resumed in a year. It took years to build this staff; it could not be rebuilt quickly. It follows that it would be nearly impossible to resume operations after a year of suspension, so that a year of suspension is tantamount to closing the facility.

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Table 14. 1 Cooperative Agreement NSF AST 0223851 Sources of New FY2005 NSF Funds (in $ k)

Total New SPO # Scientific Program Orders (SPOs) NSF Funds

1 NRAO Operations, Maintenance, and Management 45,300 Extended Very Large Array (EVLA) 8,700 ALMA Operations 1,000 Subtotal New NSF Funds SPO-1 55,000

2 Atacama Large Millimeter Array (U.S.) 49,670 3 Research Experience - Teachers and Undergraduates 193 4 Green Bank Solar Burst Radio Spectrometer - 5 MRI - Real-Time RFI Mitigation and Instrumentation - Total New NSF Funds 104,863

Table 14.2 NSF New Funding by Function (in $ k)

Materials, Salaries & Total New NSF SPO # Scientific Program Orders (SPOs) Services & Travel Benefits Funds Equipment NRAO Operations, Maintenance, and 1 36,777 17,019 1,204 55,000 Management

2 Atacama Large Millimeter Array (U.S.) 10,462 37,970 1,238 49,670

Research Experience - Teachers and 3 - 188 4 192 Undergraduates 4 Green Bank Solar Burst Radio Spectrometer - - - - Real-Time RFI Mitigation and 5 - - - - Instrumentation Total new NSF funds 47,239 55,177 2,446 104,862

Note: Total new NSF funds do not equal $104,863k due to round-off error in SPO-3.

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Table 14.3 NSF Funds (Appropriated Level Budget) by Budget Category (in $ k)

Prior Year Uncommitted Total Commitments New NSF Carryover of Available for Available for Carried Over Funds FY 2004 Expenditure Commitment from FY Funds 2004

NSF - AST Funded

Personnel Compensation 35,652 - 35,652 - 35,652

Personnel Benefits 11,587 - 11,587 - 11,587

Travel 2,446 - 2,446 - 2,446

Material & Services 52,760 56,537 109,298 11,123 120,421

Management Fee 2,617 - 2,617 - 2,617

Common Cost Recovery (200) - (200) - (200)

Device Revenue - - - - -

Research Equipment - - - - -

Total NSF AST only 104,862 56,537 161,399 11,123 172,523

NSF non-AST Funded

MRI - - - 47 47

CISE - 207 207 - 207

Education - 100 100 - 100

Total NSF non-AST - 307 307 47 354

Total NSF 104,862 56,845 161,707 11,170 172,877

Note: NSF AST does not equal $104,863k due to round-off error.

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Table 14.4 NSF AST FY2004 Carryover (in $ k)

FY 2004 SPO # Scientific Program Orders (SPOs) Carryover

1 NRAO Operations, Maintenance, and Management 1,622 GBT Student Support 50 Green Bank Track Repair Augment 4,401 * Extended Very Large Array (EVLA) 5,140 ** Subtotal SPO-1 Carryover 11,213

2 Atacama Large Millimeter Array (U.S.) 44,544 *** 3 Research Experience - Teachers and Undergraduates 160 4 Green Bank Solar Burst Radio Spectrometer 299 5 Real-Time RFI Mitigation and Instrumentation 322 Total FY 2004 Carryover 56,538

* Investigations and design studies for the best approach for permanent repair of the GBT azimuth track were underway in 2004 and should conclude in early FY2005. Contract commitments utilizing the carryover are expected by mid-to-late FY2005, with the repair work carried out in FY2006

** The FY2004 carryover is allocated to the following large production orders for which the procurement process has already started: YIG oscillators, RF AGC assemblies, UX converters, DTS transponders, L- band feed components, C-band feed components, module interface circuit board assemblies.

***The ALMA carryover is due to a delay in being able to commit funds to the antenna procurement and site construction, accumulation of budgeted contingency funds not yet allocated.

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Table 14.5 Management Fee detail (in $ k)

Management SPO # Scientific Program Orders (SPOs) Fee SPO-1 1 NRAO Operations, Maintenance, and Management 1,133 Extended Very Large Array (EVLA) 218 ALMA Operations 25 Subtotal SPO-1 1,375

SPO-2 2 ALMA (U.S.) 1,242 Total Management Fee 2,617

Note: Management Fee applied to AST Funds only. No fee is applied to SPO-3, SPO-4, or SPO-5

Table 14.6 Prior Year Commitments detail (in $ k)

Total New SPO # Scientific Program Orders (SPOs) NSF Funds

1 NRAO Operations, Maintenance, and Management 1,861 Green Bank Track Repair Augment 47 Extended Very Large Array (EVLA) 2,863 Subtotal SPO-1 Prior Year Commitments 4,772

2 Atacama Large Millimeter Array (U.S.) 6,331 3 Research Experience - Teachers and Undergraduates - 4 Green Bank Solar Burst Radio Spectrometer 20 5 Real-Time RFI Mitigation and Instrumentation - Total Prior Year Commitments 11,123

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Table 14.7 NRAO Management, Operations and Maintenance (SPO-1) Detail New NSF Funding (in $ k)

Materials, Salaries & Total New NSF SPO-1 Operational Function Services & Travel Benefits Funds Equipment

Observatory Management 3,965 4,119 323 8,407

Education and Public Outreach 376 20 5 401

Central Development Laboratory 1,353 134 12 1,499

Green Bank Operations 8,501 1,524 100 10,125

New Mexico Operations 13,654 3,819 219 17,692

EVLA 2,924 5,616 160 8,700

Computer and Information Services 1,190 628 64 1,882

Division of Science and Academic Affairs 4,457 532 306 5,295

ALMA Operations 356 629 15 1,000

Total SPO-1 new NSF Funding 36,776 17,021 1,204 55,001

Note: SPO-1 does not properly sum to $55,000k due to round-off error in Division of Science and Academic Affairs.

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Table 14.8 FY2005 Non-Programmatic Funding ($ k)

Materials, Salaries & Total New Funding Source Grant Name Services & Travel Benefits Funds Equipment

Unveiling the Progenitors and Physics of Cosmic STScI 7,504 7,504 Explosions (Frail) Identifying the Earliest Massive Starbursts NASA (JPL Spitzer) - 44,000 44,000 (Carilli) Where is the Dust and Start Formation in NASA (JPL Spitzer) - 9,800 9,800 Compact Groups of Galaxies? (Hibbard) IRAC and MIPS Imaging of High Mass Outflows NASA (JPL Spitzer) 10,500 10,500 (Shepherd)

Johns Hopkins U (NASA) Lunar Reconnaissance Orbiter (Butler) 7,844 8,459 6,000 22,303

Does Quiescent Coronal Activity Exist in late M- NASA 10,600 23,478 1,620 35,698 L Dwarfs (Osten)

New Non-Programmatic Funding 18,444 103,741 7,620 129,805 The above listed grants have been awarded or have been confirmed as being in the funding process.

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Table 14.9 Observatory WBS

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14. FY2005 Preliminary Financial Plan

Table 14.9 (cont’d) Observatory WBS

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Cosmology, Large-Scale Structure, Galaxy Formation, and Gravitational Lensing

Radio observations, unaffected by dust extinction, are able to probe the most distant galaxies and provide insights into both star formation and active galactic nuclei (AGN) in the early universe. HI studies with the 21 cm line are complementary to both optical and infrared investigations since they can detect gas- rich systems and isolated HI features. Star formation and starbursts mold the overall appearance of galaxies. It is believed that star formation proceeded at higher rates in the early universe than now.

Simulations of the appearance of the deep millimeter/submillimeter sky as viewed by the Atacama Large Millimeter Array (ALMA) and by the Green Bank Telescope (GBT) will continue as part of efforts to construct the former and instrument the latter with high-frequency receivers. The GBT will be used to measure CO emission from a sample of galaxies at intermediate redshifts, taking advantage of its broad spectral coverage and great sensitivity to prove its usefulness as a redshift machine.

A program to obtain optical identifications and spectra for 3400 radio sources detected by the Very Large Array (VLA) in the SIRTF First-Look Survey area will continue. Preliminary results from about 1000 galaxies indicate that the local far-infrared/radio correlation remains valid back to redshifts z ~ 1. The spectra are being used to calculate distances and to help distinguish between star formation and AGN as the origin of the radio emission. Extinction-free estimates of the space density and evolution of both the star-formation rate and the amount of nuclear activity in galaxies will be made for the redshift range 0 < z < 0.5.

The VLA is being used for a high-resolution (2 arcsec) deep radio survey (4 microJy rms) of the Chandra Deep Field South/Hubble Advanced Camera for Surveys Ultra Deep Field region. The radio data will be complemented by far-infrared imaging from Spitzer, X-ray data from Chandra, and deep optical imaging and redshifts from HST and ground-based optical facilities to give the most complete deep probe of the universe. The new VLA observations will address the formation and evolution of stars, galaxies, and AGN out to the epoch of re-ionization and beyond, including the relations between the formation of stars and black holes, as manifested by AGN, and their host galaxies.

Very deep VLA 20 cm observations using the A, B, C, and D arrays will be used to study the nature of the microJy radio-source population and the evolution of star-formation and black-hole-driven activity. The radio survey is the deepest radio image yet, with an rms noise level of ~2.7 microJy. The radio survey covers a special region of the Spitzer SWIRE Legacy survey in the Lockman hole. A variety of optical/near-infrared imaging and spectroscopy and CHANDRA X-ray survey data have also been assembled in this region to supplement the VLA survey.

The VLA will continue its survey covering the 3π steradians of sky north of declination -30˚ at 74 MHz in the B configuration. The observations scheduled for the next year will raise the fraction of sky covered from the current ~50% to ~90%. The 5-sigma sensitivity of the survey is 0.5 Jy/beam, and over 70,000 objects are expected to be catalogued. Data reduction is under way, and public release of the images and catalog is expected by the end of 2005.

The VLA and VLBA will be used to carry out follow-up observations of candidate gravitational- lens systems discovered in the Cosmic Lens All-Sky Survey (CLASS) and to study such properties of the lensing galaxies as dark-matter distributions in the cores.

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The Cosmic Background Imager (CBI) will be used to measure the temperature and polarization angular power spectra of the Cosmic Microwave Background (CMB) radiation from the ALMA site in Atacama, Chile. Powerful data-analysis techniques for interferometric observations of anisotropy in the intensity and polarization of the CMB will be developed. This new work will focus on analyzing the past two years of CMB polarization data collected by the CBI, as well as analyzing Sunyaev-Zel’dovich Effect (SZE) observations of a complete sample of low-redshift galaxy clusters. The CBI is well suited to make measurements on the angular scales where the polarization power spectrum is expected to peak (l ~ 900), and interferometry is a proven method to make these measurements. The CBI SZE work will extend studies previously done on objectively defined cluster samples with the Owens Valley 5.5-meter telescope as well as the CBI and aims at an improved measurement of the cosmic distance scale.

The GBT and VLA will be used to make measurements of discrete source foregrounds to the CMB in the 26 to 40 GHz frequency range. The GBT measurements will employ a new 26 to 40 GHz receiver as well as a new continuum backend which is under construction. The work will initially focus on characterizing the total-intensity properties of the discrete-source foreground. The accuracy of 30 GHz measurements of CMB anisotropy at all scales will be significantly improved by the GBT data, but the impact will be particularly notable on small scales (l > 2000).

The earliest epoch of galaxy formation (the epoch of reionization) will be studied using radio observations of molecular line, thermal dust, and non-thermal synchrotron emission from the host galaxies of the highest-redshift QSOs. The large VLA COSMOS program will begin an investigation of the evolution of star-forming galaxies and radio AGN to z = 3.

A program of searching known high-z CO emission-line galaxies for hydrogen cyanide (HCN) emission will continue with the VLA. To date HCN has been detected in three such galaxies with 2 < z < 3. There are another three with sufficiently high CO luminosities to justify HCN searches.

The GBT will be used to study CO emission in a number of high-z galaxies. In known CO emission-line galaxies, quality J = 1-0 profiles will be used to search for evidence of rotating disks of molecular gas. In candidate galaxies the new Ka-band receiver will be used to search for CO emission.

Detailed mapping of the structure of the local universe will be extended in distance with the added sensitivity of the GBT to 21-cm radiation from HI in galaxies. The distance scales provided by Type Ia supernovae and by the luminosity/HI line-width relation will be unified. New GBT and Arecibo HI observations and new SNIa luminosity data in the same galaxies will be utilized.

Studies of the radio properties of medium-distance rich clusters using deep VLA 20 cm observations will continue. These clusters show an increase in radio activity over similar nearby clusters; the nature and origin of the activity isv not clear. New data to complement this work will be obtained with Spitzer and various optical telescopes. X-ray, submillimeter, and optical/near-infrared surveys will also help us understand these fields.

VLA observations at 20 cm, 90 cm, and 4 m wavelengths will be used to test the idea that a diffuse relativistic plasma is a general feature of rich clusters and is not associated only with obviously merging clusters. The dynamics of the Cygnus A cluster of galaxies will be studied using a new set of radial velocities from the WIYN telescope.

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The VLBA will further investigate the high-redshift HI absorption against the radio galaxy B2 0902+343 at z = 3.4, which was first detected with the VLA. The goal is to confirm the substructure hinted in follow-up VLA B- and C-array observations with a spectral resolution of 12 kHz. The absorbing system is perhaps the signature of a forming dense cluster of galaxies.

Radio Galaxies, Quasars, Active Galaxies, and Gamma-Ray Bursts

Powerful radio jets are ubiquitous features of many AGN. They serve as tracers of the energy transport from supermassive black holes (believed to be responsible for the AGN activity) into their surrounding environments. A number of multi-wavelength studies will be undertaken, aimed at gaining a more fundamental understanding of the physics of AGN jets. New Spitzer observations will detect and resolve, for the first time, infrared emission from a number of well-known radio jets and hotspots. We will combine these data with Chandra X-ray, Hubble Space Telescope (HST), VLA, MERLIN, and VLBA data to constrain jet models and to study particle acceleration in the hotspots.

Deep Chandra and VLA images of a number of well-known quasar jets are being obtained and analyzed. These observations are aimed at detailed studies of the particle acceleration processes responsible for the emission from radio to X-ray wavelengths. Continued Chandra, HST, VLA, and VLBA monitoring of the well-known jet in the elliptical galaxy Virgo A will track morphological and spectral changes in the jet. Chandra and VLA imaging of extended emission in a new population of blazers plus samples of aligned and misaligned low-luminosity (Fanaroff-Riley type I) radio galaxies will test models of radio sources. These complement ongoing studies of the jets in high-luminosity (FR type II) objects. Jet emission from the highest-redshift compact radio sources known is to be identified using archival and new VLA data. New radio jets will be followed up with Chandra imaging to test models for the production of X-ray emission in quasar jets and to set constraints on key physical parameters of the jets (speed, magnetic field, and particle content).

Several studies of the ISM in radio galaxies and quasars using continuum and polarimetric observations from the VLA and VLBA will continue. In particular, the question of the low- frequency opacity source in Compact Steep Spectrum (CSS) sources (free-free vs. synchrotron) is being investigated. This study uses a combination of VLA, MERLIN, and HST observations. CSS sources are thought to be young versions of the large-scale radio sources in AGNs, but their development is poorly understood.

The VLBA is being used at frequencies from 1.6 to 86 GHz in an attempt to discern the three-dimension structure of gamma-ray blazar jets, via measurements of variations in component proper motion, linear polarization (magnetic field) structure, and radiative-transfer effects (e.g., Faraday rotation). Typically, the lower-frequency observations (< 10 GHz) cannot adequately resolve the transverse and longitudinal structure of these jets and higher-frequency observations lack sufficient surface-brightness sensitivity to see more than just the brightest of the jet components, which quickly fade as they move out. Thus, at any single observing frequency, it is difficult to develop a complete geometrical and evolutionary model of the jet material and the components (shocks) which move through them. It is desirable, therefore, to synthesize jet models from the widest possible range of frequencies. Together with isolation of stationary components (including the observed “core” at each frequency), the measurement of component motions (apparent velocities and accelerations) over greater distances along the jet should yield clues about the jet structure in three dimensions. The high level of aberration in these well-aligned jets should show polarization degree and orientation effects which correlate with the geometrical picture and thus strengthen the models. Better geometrical models of these jets will yield better physical and

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phenomenological deductions about optical and Faraday depths, magnetic field ordering, gamma-ray emission origins, dependence of jet properties on optical identification, etc.

The VLBA will be used to study the fine-scale structure of AGN. Visibility data will be used to examine most compact features in 250 quasars and active galaxies. With projected baselines out to 440 million wavelengths (15 GHz), the VLBA allows us to investigate source structure on angular scales as small as about 0.1 mas. Radio/X-ray properties of radio-loud AGN will be also under analysis. It is known that radio and X-ray luminosities correlate (e.g. Brinkmann et al. 1997, A&A, 319, 413). We will check whether this correlation becomes more pronounced if the correlated flux density from the longest VLBA baselines (which see the most compact emitting regions) rather than the total flux density is used. This analysis will help to reveal the source of the X-ray emission from AGN.

During the previous year, strategies were developed for conducting layered VLBI surveys of 1.4 GHz sources in the NOAO Bootes field. VLBA observations sequentially targeted tens of sources stronger than 10 mJy and spread over 9.0 deg2, detecting about one source in three. VLBA+GBT observations simultaneously targeted tens of mJy or sub-mJy sources spread over 0.28 deg2, detecting about one source in seven. Each VLBI detection is an accretion-powered AGN or a candidate AGN and helps to anchor the optical NOAO field to the radio International Celestial Reference Frame. Layered VLBI surveys of 1.4 GHz sources in the Spitzer First-Look Survey have begun and will be completed in the upcoming year.

Data from the VLA and Chandra have been obtained for a study of the accretion history of supermassive black holes. Five fields in the Lockman Hole-NW contain 31 X-ray sources stronger than 10-14 ergs cm-2 s-1 in the 2-8 keV band, and 5 GHz A configuration images with 14 microJy rms noise cover their positions. The radio/X-ray ratios of the AGN cores constrain the radiative efficiency of their accretion.

Existing data from the VLA and various optical telescopes will be used to study the dependence of the radio luminosity at the FR I/II morphology change on optical galaxy luminosity. The nature of a new population of very large FR I galaxies will be studied using a sample of B2 radio galaxies and low- resolution VLA images.

GBT and VLA continuum data will be combined for several giant FR I radio galaxies to allow studies of their large-scale spectral-index distributions. Also accurate polarimetry in regions of low intensity will be compared with predictions of physical models of their energy losses, jet propagation, and evolution. Multi-configuration, multi-frequency VLA imaging and polarimetry of jets in FRI radio galaxies, augmented by data from the Pie Town link and GBT where necessary, will be fitted by jet models which account for the effects of relativistic aberration and internal velocity fields. In concert with Chandra observations of the thermal X-ray emission from the galactic environments of the radio sources, this will allow derivation of physical parameters for the underlying flows,

The GBT will be used to measure large Faraday rotation measures in the 103-107 rad m-2 range from AGN. A sensitive method based on broad-band spectrometric observations will be used. The survey will provide valuable information about the density-weighted magnetic field along the line of sight in compact structures of AGN. In particular, a search will be performed for expected but not yet confirmed high values of magnetic field close to the core.

A complete sample of nearby radio galaxies will be studied using the VLA and VLBA. This sample is well suited for statistical studies testing unified schemes and the nature of radio galaxies as a function of

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their luminosity and large-scale radio morphology. New Compact Symmetric Objects (CSOs) will be identified and their growth studied with the VLBA. These measurements will be used to establish ages for their radio emission. Studying CSOs, which are thought to evolve into FR II radio galaxies, will place constraints on unified schemes and the evolution of radio galaxies.

VLBA follow-up observations will be performed to try to confirm the binary black-hole system 0402+379 discovered by Maness et al. (2004, ApJ, 602, 123). This object is a CS0, but with large-scale structure. VLBA observations taken in 2003 revealed two central compact flat-spectrum components, which we identify as possible AGN. At a separation of just 7 parsecs, this would be the closest active binary system known by a factor of more than 1000. The existence of such a system would have profound implications for LIGO, LISA, and other missions hoping to detect gravitational radiation.

Using VLA archive data, limits on the number of extragalactic transient radio sources will be derived. This experiment uses survey observations of nearby clusters of galaxies reduced as a series of 30 second snapshot observations. Reduction of existing data will continue through 2005. Short-term transients can be detected by this technique.

A VLBA program has been carried out to image a sample of 15 galaxy mergers each containing at least one compact nuclear radio source. The merger process produces copious amounts of gas that may be used to fuel a central black hole if one exists in either of the incoming galaxy nuclei. The presence of a milliarcsecond radio source in the nucleus of a merger would indicate the presence of a black hole in at least one galaxy and would show that the active nucleus and an extreme starburst can coexist. Preliminary results on the first eight galaxies show that at least two contain active nuclei. The data analysis, imaging, and interpretation will be completed during 2005.

Some low-luminosity AGN may contain black holes with masses of a million solar masses or less, smaller than the 4 million solar-mass black hole at the center of our own Milky Way. Previously, no black holes with masses less than a million solar masses had been confirmed in galaxy nuclei. Sloan Digital Sky Survey data now have been used to select a sample of 19 AGN whose line widths indicate black-hole masses between 80,000 and a million solar masses. Since this is the first sample of black holes of such masses, the properties of the environments of the low-mass black holes are completely unexplored. The relatively high observed X-ray luminosities are near the black holes’ Eddington luminosities, yet FIRST upper limits indicate that the galaxies are relatively radio weak. A sensitive VLA survey of these galaxies with low black-hole masses will be carried out to determine whether they contain compact radio sources, to measure the ratio of radio to X-ray emission, and to constrain models of the accretion processes around the low-mass black holes.

During the past year an extensive VLA program has been carried out to search for intraday variability from low-luminosity AGN. The presence of intraday variability in these galaxies, typically only a few millijansky in total flux density, would indicate the presence of nuclear radio sources with sizes of tens of microarcseconds. Such a size measurement would have significant impact on the models for accretion processes in these objects. VLBA imaging already shows that the radio sources are smaller than a few hundred microarcseconds, but studies of variability are the only means of determining smaller source sizes. Final data analysis will be completed and the results of the variability search will be published during the proposal period.

The enigmatic AGN PKS 1413+135 is being studied with multifrequency data from the VLBA, the Green Bank Interferometer (GBI), and RATAN. We will look for possible rapid deceleration of the jet as it

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leaves the central engine by analyzing the detailed structure revealed in VLBA mapping and rapid flux- density changes observed by the GBI at X-band (with almost no changes at S-band). The possibility of helical structure in the jet will also be investigated along with the spectral aging of the jet.

The core of the merger galaxy Arp 299 is being monitored at 6-month intervals using the VLBA and GBT in order to search for new supernovae and study the evolution of this “supernova factory.” Results from December 2003 indicate that the most recent supernova is fading fairly rapidly, having decreased in 8 GHz flux density by nearly 50% in the seven months since May 2003. The multiple images also will be stacked in order to reveal fainter young supernovae than can be found in individual images.

The effort to study jet bases at 43 GHz will continue with high-sensitivity observations of M84 using the VLBA, Effelsberg, and the GBT. Another new attempt will be made later in 2004 with multiple days of dynamically scheduled VLBA time. Meanwhile, M87 has been used as a calibrator for these observations and, along with data from other observations in the archive, data from multiple epochs now exist. The radio structure is clearly changing and there is good transverse resolution. A VLBA movie will be made of M87.

Following up the observation of free-free absorption of the milliarcsecond-scale counterjet in 3C 84, presumably by the accretion-disk region, efforts are being made to use counterjet absorption to detect spectral lines. Observations have been made in an attempt to detect molecular lines near 15 GHz. Preliminary indications are not good, but the reduction of the data continues. An effort to determine if there is time evolution of the free-free absorption continues.

The relatively nearby superluminal source 3C 120 continues to provide interesting constraints on jet physics. A theoretical analysis of helical instabilities in the inner few parsecs of the jet is in publication as is an analysis of the implications of X-ray detections of features on kiloparsec scales. The first paper helps constrain parameters such as the sound speed in the jet. The second provides information about the emission mechanism. Meanwhile, monitoring observations continue at 1.7 GHz with the VLBA, and a multi-day set of 327 MHz VLBA observations to delineate the structure between about 0.5 and 4 arcseconds is being reduced.

A Chandra X-ray survey of optically inactive galaxies has found five ultra-low-luminosity AGN candidates which have X-ray luminosities of only 10-10 to 10-7 times the Eddington limits of the central black holes. Typically low-luminosity AGN are relatively radio loud, indicating different accretion and emission processes than in powerful AGN, which radiate near their Eddington limits. For this sample of even lower-luminosity objects, sensitive VLA imaging will be used to determine whether any radio sources are centrally located and are AGN rather than X-ray binaries (which should be radio “quiet” at the galaxy distances). If the AGN are detected, their radio/X-ray ratios will be determined and compared to the generic low-luminosity AGN. This will show whether the trend of radio loudness continues in even lower-luminosity objects and whether the ultra-low-luminosity objects are controlled by the same physical processes as their somewhat more powerful cousins.

Radio-loud quasars are thought to have their jets pointing toward us, as confirmed by the apparent superluminal motions seen in many objects. Radio-quiet quasars are thought to have similar orientations, an inference supported by similar radio variability properties. However, superluminal motion has never been detected directly in the radio-quiet quasars, which are quite weak for good VLBI imaging. A sample of compact radio-quiet quasars will be imaged with the new High Sensitivity Array (HAS) of VLBI telescopes (incorporating the VLBA, the VLA, the GBT, Effelsberg, and Arecibo), to see whether any

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have compact jets with secondary components whose positions might be measured accurately. Follow-up observations will be made of those objects with significant secondary components in order to determine whether superluminal motion does, in fact, exist in the radio-quiet objects.

The VLA and VLBA will be used to investigate radio sources that may be candidates for gamma-ray sources to be detected by the future Gamma-ray Large Area Space Telescope (GLAST), due for launch in 2007. A second epoch of VLBA imaging will be carried out for new candidate identifications for gamma- ray sources found with the Compton Gamma-ray Observatory. The purpose of the multi-epoch VLBA imaging is to determine whether the weaker radio sources identified with gamma-ray emitters have component motions similar to those of the stronger identifications, and whether this may be used to help identify GLAST sources. The VLA will be used to make a snapshot survey of a thousand flat-spectrum sources at southern declinations to complement the similar surveys used to search for gravitational lenses in the northern sky. This survey will create a data base of source positions, images, and spectra which can be used to find candidates for the weaker gamma-ray sources that will be discovered by GLAST.

Low-frequency VLA observations will be made of the Centaurus cluster. Not to be confused with Cen A, this cluster contains the less-famous radio galaxy PKS 1246-410 which shows a strong interaction with the X-ray emitting gas. A filament in the X-rays appears to encircle the radio lobes. Chandra will be used to obtain a moderately deep 200 ksec observation of the Centaurus cluster to aid in the detailed comparison between X-ray and radio emission. Faraday rotation- measure studies of radio sources embedded in A2597 and other clusters will be used to estimate magnetic field strengths and topologies.

The VLBA will continue to observe continuum emission and HI absorption from ultra-luminous infrared galaxies. Such observations require both high angular resolution and extremely high sensitivity, achievable only by combining the VLBA with several large-aperture instruments such as the VLA, the GBT, and Arecibo. The objects of study, among the most luminous in the universe in the infrared, are generally believed to result from mergers and/or close encounters between galaxies. The planned observations will improve our understanding of the merger process and how it may lead to a starburst or to the formation of one or more AGN.

In 2005 the VLA (in some cases with the Pie Town VLA link) will be used to observe a sample of radio galaxies in HI in order to accurately determine the location where WSRT observations have detected very broad (~1000km/s) HI absorption. The results can help us determine which of the various proposed mechanisms is responsible for this absorption.

The nearby (z = 0.1685) gamma-ray burst of 29 March 2003 has presented a unique opportunity to study an event with unprecedented clarity. This burst reached flux-density levels at centimeter wavelengths more than 50 times brighter than any previously studied event. Global VLBI observations at multiple epochs have been used to measure the source diameter and proper motion of GRB 030329 at sub- milliarcsecond levels. These observations can constrain theories describing the dynamical evolution of the fireball. Future VLBA observations will be made that image the expansion of GRB 030329, constrain proper motions, and search for possible jet components.

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Normal Galaxies

A complete sample of galaxies brighter than K = 11.25 from the 2MASS is being identified with radio sources in the NVSS. Separate luminosity functions of galaxies whose radio sources are powered by star formation and by AGN will be determined, the latter with unprecedented accuracy. The K-band luminosity is a good indicator of total stellar mass independent of star-formation history, while the radio luminosity of star-forming galaxies is proportional to the current star-formation rate. Thus the radio/K-band ratio is an extinction-free indicator of the normalized star-formation rate. The behavior of this indicator will be investigated as a function of galaxy morphological type, mass, and environment for clues about the global properties of star formation in the universe today.

The VLA will be used to study the kinematics of superthin galaxies by probing their HI emission with unprecedented resolution and sensitivity. The systems to be studied range from “isolated” to “mildly interacting” to “being in a group” and will also include a superthin galaxy which shows a recently detected polar ring. These systems are among the most dark-matter-dominated galaxies known and exhibit highly interesting dynamical features such as warps (even in the “isolated” galaxy).

Galaxy dynamics as they affect measured HI line profile widths will be modeled with the aim of better understanding the connection between line width and total luminosity.

The neutral hydrogen of NGC 6503 will be imaged and analyzed using data already obtained with the VLA. The data will be investigated for any connection to a nearby strong quasi-stellar source. Preliminary results show a lack of absorption by Galactic hydrogen which is very surprising at this modest Galactic latitude of 30 degrees.

The VLA will be used to map the HI emission and study the ISM stability in a sample of edge-on galaxies spanning a range of masses. Previous analysis of these systems suggests a sharp, mass-dependent transition in the structure of their dusty ISM, with well-defined low-scale-height dust lanes in the more massive galaxies and a more diffuse, broader dust distribution in less-massive galaxies. The VLA sample targets galaxies on either side of the proposed transition and will provide data for evaluating the ISM turbulence, disk stability, and star-formation efficiency as a function of dust-lane morphology.

A large number of interacting and peculiar galaxies with existing VLA HI maps collected from the “HI Rogues Gallery” have been targeted for far- and near-UV imaging by the GALEX Nearby Galaxies Survey. The UV data will be compared with the distribution and kinematics of the cold atomic gas in order to investigate whether the “star-formation law” and “star-formation threshold” determined empirically for disk galaxies pertain as well to the extra-disk star-forming regions found in many peculiar galaxies. These data will help constrain the underlying physical basis for such star-formation laws.

The recent discovery of a population of hydrogen clouds in the vicinity of the Andromeda galaxy has stimulated interest in the general question of the presence of neutral hydrogen clouds which might be associated with a spiral galaxy but which lie well outside the galaxy’s disk. Such clouds could be of fundamental importance to the evolution of a galaxy since an interaction could easily produce observable asymmetries in the morphology, and they have been postulated as a possible agent for the promotion of star formation. To search for additional examples of hydrogen satellites, observations of the integrated HI profiles of 100 galaxies have been made using the GBT. The new data will be compared with profiles measured previously with the 140-ft telescope. Differences between the integrated emission profiles in

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the two beams will reveal the presence of material on an angular scale of 10 - 20 arcmin. This search is sensitive to clouds of small hydrogen mass but does not allow an individual cloud to be imaged. To do that, the VLA was used to map the HI in four galaxies which have suggestive signatures in the WHISP survey. Two of the spirals show small, faint HI features but with low signal-to-noise ratios. The other two objects are instances of an interaction between a galaxy and an associated HI cloud; the HI cloud has no obvious optical counterpart in either case. These data will be used to produce new images of the hydrogen environment of each galaxy.

An unbiased HI survey of late-type massive low-surface-brightness (LSB) galaxy candidates using the GBT will be carried out to determine the objects’ redshifts and total masses. The atomic and molecular gas distributions of massive LSB galaxies will be determined as well as their continuum emission.

Data from the VLA and the Effelsberg 100m telescope will be combined to yield high-resolution (a few arcseconds) radio-continuum and spectral-index maps of the nearby spiral galaxy M51. These will be combined with a wide array of optical, UV, and near- and far-infrared observations (most notably from the Spitzer Space Telescope) to compare the best known star-formation tracers at spatial resolutions below 100 pc.

Late in 2004 a challenging experiment with about 50 hours of exactly simultaneous observations with the VLA and the Chandra X-ray Observatory will be carried out. M31*, the faint nuclear radio source in the center of M31, will be imaged at 6 cm with the VLA in A or B array and observed simultaneously with Chandra. The goal is to detect variable radio and X-ray emission and to accurately place the radio source in the rich field of X-ray sources, yielding the first reliable radio/X-ray association and confirmation of the black-hole nature of the source. Furthermore, a sensitive 6 cm Mark 5 pilot project will be carried out by the EVN to determine the milliarcsecond morphology of the nuclear source, possibly detecting a core- jet structure, again to constrain the proposed low-luminosity nuclear black-hole models for the radio source and to compare the nuclear source with Sgr A* in the nucleus of the Milky Way. The study of these low-luminosity black holes will be critical in unifying and distinguishing supermassive black holes in the centers of normal galaxies.

The GBT will be used to discover water-vapor maser systems in AGNs farther than 150 Mpc. These galaxies will then be candidates for detailed VLBA studies which can be used to pursue black-hole mass, accretion-disk geometry and dynamics, and distance to the host galaxy. Ongoing observations with the VLBA are being used to study the accretion disks of known water-maser systems. The GBT will also be used to characterize the maser emission in known systems. As the quality of ongoing surveys continues to improve, the number of known water- maser systems is increasing; more than 60 extragalactic masers are now known. Statistical studies will be used to reveal the links between maser occurrence and other galaxian properties and will further our understanding of these important astrophysical probes.

Studies will derive the chemical-enrichment history of dwarf galaxies in the Local Group. The method, currently being applied to Fornax and the LMC, utilizes a detailed calibration of the infrared Ca triplet in red giants together with precise color-magnitude diagrams to disentangle the age-metallicity degeneracy in old and intermediate-age populations. A study of kinematics and morphology of peculiar Virgo Cluster galaxies will also continue. This includes objects with evidence of tidal interactions and mergers. Measurements of the gas distributions and kinematics of HI, HII, and CO together with accurate stellar kinematics via integral-field spectroscopy are yielding results that lead to possible scenarios to explain the observed peculiarities.

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The Interstellar Medium, Molecular Clouds, Astrochemistry, Cosmic Masers, Star Formation, and Stellar Evolution

The GBT will be used to measure hydrogen clouds that lie in the interface between the Galactic disk and its hot halo. Several hundred of these clouds will be identified and, with GBT 21cm observations, their sizes, masses, and other physical properties will be derived. VLA HI observations will be combined with the GBT data to reveal the fine structure in the cloud cores and refine estimates of temperature and pressure through measurement of HI absorption against distant continuum sources.

The GBT will be used to investigate the structure of several high-velocity HI clouds which appear to be interacting with the Galactic halo, perhaps because they are primitive objects being accreted by the Galaxy. With the GBT data it will be possible to estimate the three-dimensional velocity of the clouds by examining the change in their projected radial velocity with position.

The VLA will be used to map Galactic HI absorption structures on scales from 0.01 to 100 pc by measuring the HI absorption towards extragalactic radio sources in a small area of the sky.

The Spitzer Space Telescope, the Combined ARray for Millimeter Astronomy (CARMA), and the VLA will be used to image outflows and disks associated with luminous young stellar objects (YSOs). The Spitzer IRAC and MIPS cameras will be used to study outflow collimation using the highly excited CO fundamental band and compare the collimation with better-understood outflows in lower-luminosity sources. Because the vibrational excitation of CO requires temperatures of greater than 500 K, one should easily be able to separate the outflow from the ambient gas. Spitzer will also be used to identify the outflow-powering sources and derive their mid-infrared fluxes and luminosities. The CO outflows plus 1 and 3 millimeter continuum emission from thermal dust will be imaged with CARMA at resolutions of 1" to 10" depending upon the size scale of the source structure. The VLA will provide complementary information about the compact region immediately surrounding the central protostar with resolutions of 0.05" to about 1". VLA observations from 7 mm to 6 cm are used to image ionized gas in the ultracompact HII region within a few 100 AU of the central star as well as ionized gas in collimated jets which at least partially power the more extended molecular outflow. Observational efforts focus on sources that are well-suited for study with an interferometer and may provide specific constraints for theories of outflow/jet production mechanisms. The observational constraints derived from the VLA, CARMA, and Spitzer images will be used to examine the relationship between stellar mass, accretion rates, and the ejection-to-accretion ratios in molecular outflow sources of low and high luminosity.

A study of the earliest stages of low-mass and high-mass star formation within the Milky Way will use radio continuum, submillimeter dust continuum, and molecular line emission to probe the physical structure of star-forming cores. An NRAO staff member, who is also a member of the Spitzer Space Telescope “Cores to Disks” Legacy Team, will follow up with the VLA a new class of deeply embedded infrared objects that have been discovered in previously classified pre-protostellar cores. Radiative- transfer models of dust continuum and molecular line emission will be used to constrain the density, temperature, kinematical, and chemical evolution of star-forming regions.

Proper motions and polarizations of water masers near low-mass YSOs are being observed with the VLBA and the VLA, and these observations will continue into the next year. These proper- motion studies are currently the best way to study the base of the jet near the forming star and accretion disk because of their unsurpassed angular resolution. Polarization studies of the masers in these objects are

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also unique because there is no other method to probe the magnetic field within a few AU of the forming star.

VLBA phase-referencing techniques are being refined to enable imaging of Galactic water masers at a resolution of 10’s of microarcseconds. Proper-motion and parallax measurements of water masers using these techiques will yield distance measurements out to many kiloparsecs, with implications for studies of Galactic structure and rotation, and of structure and evolution of circumstellar shells and outflows.

Study of the fine-scale structure in the Galactic magnetic field will continue, using observations of the Zeeman effect in water-maser lines with the VLBA. If the magnetic field is tangled, one obtains only a signed average over the field in whatever spatial region is sampled. Observations with higher angular resolution sample smaller regions and thus allow a higher lower limit to be established; comparison of the results obtained with varying resolutions allows conclusions to be drawn concerning the spatial scale of field tangling.

The only available probe of the inner AU or so of a protostar remains water-maser emission. A program of mapping masers over time to determine true space motion of the flow continues, using the VLA, the VLBA and the Pie Town link between them. Class 0 sources are thought to be in an active accretion phase, with observed highly collimated powerful molecular outflows. These flows, and the protostellar jets which power them, are thought to play an essential role in the evolution of a protostar into a star approaching the main sequence. In the current paradigm, the jet dominates angular-momentum transport in the accretion disk; it regulates protostellar rotation so that the star continues to accrete without reaching breakup speeds. As the outflow dissipates angular momentum, it also dissipates the parent core. Therefore, jets determine the final stellar mass by controlling infall and outflow motions. The acceleration and collimation of the jets probably involves magnetohydrodynamic processes in the vicinity of the stars. Until ALMA is built, the only means we have for imaging these processes is observing water-maser emission generated at the shocks where the jet impinges on the cloud, whether these lie where the outflow shocks ambient material or at the protostellar accretion shock. We have use the VLA/VLBA/Pie Town link to investigate this region in a number of objects with Class 0 SEDs; all show that the masers occur in shocks propagating into a molecular sheath surrounding the outflow jet. Where the stellar position is known, it can be shown that the masers occur within several score of AU of the star; some appear to coincide with the stellar position. These observations support an “X-wind” theoretical model of outflow initiation. Magnetic fields are expected to figure in this model. We have detected Zeeman structure in one strong maser component near IRAS 16293 and estimate the line-of-sight component of the field to be 40 mG.

Recently it has become possible to investigate maser proper motions in regions forming more massive stars. Generally, the maser components are more numerous and appear to evolve more quickly in these regions. In one region of note, a complex maser system produces masers over a fairly broad velocity range in a complex pattern. However, a nearby maser at extremely high velocities has appeared regularly which apparently is not associated with the main complex and its millimeter continuum core (it is moving towards it!). Observations at OVRO this year detected a weaker continuum component which coincides with the extremely high-velocity maser (nearly 100 km/s removed from the main complex). This mysterious new object may represent maser activity in material falling onto a star in its earliest stage of creation.

Several coordinated projects studying the atmospheres and mass-losing regions of Mira stars using the VLBA and infrared interferometers will continue. SiO masers, which can be studied using the VLBA,

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arise between the outer parts of the molecular envelopes, studied by near-infrared interferometers (IOTA, CHARA), and the dust-forming regions, studied by mid-infrared interferometers (ISI, VLTI/MIDI). These coordinated observations can help in the understanding of the mass-loss mechanisms in these evolved stars which are one of the major contributors to the interstellar medium and which are currently poorly understood.

Formaldehyde (H2CO) 6 cm maser emission is known to exist in only five Galactic HII regions. A number of these were found with the VLA more than a decade ago. The nature of this rare Galactic maser remains a mystery today. No quantitative model can explain the maser emission. Based on recent Arecibo and GBT surveys, 15 candidates for possible H2CO emission lines have been identified and will be observed with the VLA in its A configuration. The high resolution of the VLA is necessary to resolve out the confusing strong H2CO Galactic absorption lines.

The GBT will be used to search for and study complex organic molecules such as the three-carbon sugar, glyceraldehyde. It is evident that complex molecules, some of which are biologically significant, exist in certain interstellar molecular clouds. The discovery of families of increasingly complex molecules, such as propynal (HC2CHO), propenal (CH2CHCHO), and propanal (CH3CH2CHO), is helping to illustrate the mechanisms by which these molecules form.

Magnetic fields are believed to play essential regulatory roles in many aspects of star formation, but field strengths are extremely difficult to measure at the molecular cloud densities actually relevant for the star- formation process. The Zeeman effect in CCS may be the best indicator of field strength in these environments: CCS emission is strong in low-mass, starless dense cores, but its chemistry limits the number of low-mass, Class 0 protostars with which it has been associated to only the very youngest sources, and these are too weak for the Zeeman effect to be measured with current instruments. In an attempt to identify protostellar sources with CCS emission strong enough for measurements of the Zeeman effect, the GBT will be used to search for CCS emission from two new populations of sources: high-mass protostellar objects (HMPOs) and infrared dark clouds (IRDCs). The CCS measurements will also be extremely useful for determining the chemical evolutionary states of these relatively unexplored classes of objects for comparison with the well-studied chemistry of low-mass dense cores.

The unambiguous detection of gravitational infall in star-forming regions through molecular emission lines is complicated by other motions in the gas, such as rotation and outflow. Ultimately the only unambiguous way of detecting whether gas is infalling is to carry out absorption (rather than emission) spectroscopy against a continuum source associated with the forming protostar, such as its circumstellar disk. Any blueshifted absorption is then clearly outflow and redshifted absorption will be infall; material in rotation about the central object will have motion perpendicular to the line of sight and will contribute to absorption at the systemic velocity. The CFA Submillimeter Array will be used to search for such infall signatures toward the deeply-embedded protostar IRAS 16293-2422 and the Class I/II transition object HL Tau.

The light element 3He is produced in significant amounts during the era of primordial nucleosynthesis. This abundance is then altered by nuclear processing in stars. The current hypothesis is that there is approximately zero net gain in the processing of 3He over the lifetime of the Galaxy. This conclusion is based on measurements of 3He in Galactic HII regions that reveal no radial gradient, 3He/H abundances that are consistent with primordial values determined using other methods (e.g., CMB experiments such as WMAP that measure the photon-to-baryon ratio), and evidence that mixing in low-mass stars inhibits the production of significant quantities of 3He, first predicted by standard stellar-evolution models. This

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scenario can be confirmed directly by observations of 3He in its main source, low-mass stars, or in planetary nebulae (PNe), the evolutionary stage during which the 3He is thought to be expelled into the ISM. Such observations are extremely challenging, and to date 3He has only been detected in one object, NGC 3242, with tentative detections in two PNe.

In the next year 3He abundances in PNe will be investigated using the VLA, the Arecibo telescope, which is now able to observe up to 10 GHz and covers the 3He+ spectral transition at 8.665 MHz, and the GBT. Each of these instruments has unique capabilities. The high spatial resolution of the VLA allows us to probe PNe with smaller angular sizes, Arecibo has the best sensitivity with its large collecting area, and the unblocked aperture of the GBT will improve the spectral baselines that have limited our sensitivity in the past. The goal is to increase the sample and quality of 3He+ observations of PNe and to make connections with optically observable quantities, such as N/O ratios, that have been extensively explored in PNe.

Analysis of the 2mm bandscan spectrum observed at high resolution and sensitivity over the 40 GHz window 130 - 170 GHz and toward eight different sources with the former NRAO 12 Meter Telescope is now essentially completed. It has detected a total of 15,000 lines. The comparison of observed with predicted lines for about 1200 molecular species, based on the binomial theorem, has revealed at least two dozen new species whose identification appears secure, the probability of seeing the observed lines by chance being less than 1 in 1000. The method correctly predicted the two species propanal and propenal recently seen in SgrB2. These results will produce a series of identification papers of new species and are expected to offer new insights into grain chemistry. As an outgrowth of this work, a large catalog of molecular frequencies, line strengths, and energy levels covering the Q, 3 mm, 2 mm, and 1 mm bands will be produced as a tool for the ALMA array.

A search is scheduled on the GBT this coming winter for the fine-structure transitions of atomic hydrogen 2 2 2 2 represented by n p3/2 → n s1/2 and n p1/2 → n p1/2, which occur in the radio range for 2 <= n <= 10. The fine structure has never been detected astronomically, yet the 1 GHz transitions offer a potential test of QED through the Lamb shift, and the fine-structure proper at 10 GHz gives information on the value of the fine-structure constant. The 10 GHz transitions also are a unique probe of physical conditions inside HII regions. The 10 GHz lines are particularly important because they permit the low-lying n levels of H to be probed by radio techniques. The combination of large line widths (400 MHz at 10 GHz) arising from the short lifetime of the 2s to 1s transition and the three widely spaced hf transitions, covering a range of 115 MHz, together make for a line with a complex shape, ~800 MHz wide, and expected to be very weak. The search will be daunting from the technical standpoint. The lines may be in emission or absorption depending on a variety of conditions, and probably less than 30 mK. The line/continuum ratio does not resemble usual forms because in the present case equilibrium is not established between the 2s and 2p levels, even in the presence of the 104 K microwave radiation field. So, the 2p levels are drained by Ly α emission faster than the microwave field can return these states to 2s via either absorption or 2 2 2 stimulated emission. Pumping of the p3/2 state could make the s1/2 → p3/2 absorption even stronge or could produce stimulated emission, possibly sending it into emission. At much higher densities than found in HII regions (> 2x1011 cm-3) collisions will establish thermal equilibrium between the 2s and 2p states. A major uncertainty is the unknown HI density in HII regions.

Stars are the fundamental objects of our Universe, and their births and deaths provide its pulse. How do dense cores of molecules and dust form, and how are they transformed by the stars created within them? How does the character of star formation fuel a transgalactic starburst? How and in what form do

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moderately massive stars return material to the interstellar medium? What is the influence of star deaths upon star formation within a galaxy and how does stellar death mold its form?

Before a molecular core is lit by the fires of its firstborn star it has transformed itself from a cold and barren core to an expectant parent—what are the changes which initiate this transformation? Using the VLA, OVRO, CSO, and the GBT, a program to investigate chemical change in pre-protostellar cores has begun. Observations of molecular distributions will be contrasted with existing observations of the distribution of dust and compared with models derived from those observations to investigate the role of + molecular depletion. Observations of ammonia (VLA) and the related N2H molecule (OVRO) in one core forming a very low-mass star have revealed that both molecules are depleted by orders of magnitude in regions where the density exceeds about 1.5 x 106 cm-3. Depletion is so complete that no known molecule can be used to trace the core kinematics, with the possible exception of the exceedingly + difficult-to-detect H2D molecule. Is depletion a feature of pre-protostellar cores on the verge of star formation? The aforementioned survey of the densest cores from a recent compendium has commenced to answer this question.

In warmer cores, depletion may not play a significant role in cloud evolution. To study this, a complete + + sample of young massive star-forming regions imaged in dust and the lines of HCO J=3-2 and N2H J=1- 0 and J=3-2 will be compared to determine if depletion plays any role in their chemistry. If CO becomes + + + depleted, HCO will follow and N2H will strengthen; if depletion is unimportant, N2H will remain a minor species.

The youngest stars have not yet heated their birthplace, nor have they even accreted most of their mass from it; they inhabit the coldest of molecular-cloud cores. Within these cores, the spectral energy distribution has yet to be shaped by the star; it peaks in the submillimeter with a characteristic temperature of only tens of degrees Kelvin. Cores showing these so-called ‘Class 0’ spectral energy distributions (SEDs) have been targeted for ammonia imaging with the VLA; maps of another half dozen are scheduled for observation late this summer. Apparently simple cores, characterized by cold dust and bipolar flows, have been selected to determine the rotational properties of the cores in these early stages. As material has presumably not yet settled into a circumstellar disk, the angular momentum of the parent cloud may be measured through the ammonia images and contrasted to properties of the bipolar flow. An earlier survey which presented VLA observations of linear gradients in the single-protostellar objects HH211, HH212, and HH111 has been extended to measure gradients in other cores, including NGC 2023-mms, HH24-25 cores, L1634, and IRAM 04191; a link will be demonstrated between source age, outflow momentum and outflow character in this enlarged set of sources. This further set includes multiple objects; we hope to discover how formation of multiple objects alters the angular momentum and energy budget among circumstellar gas, embedded sources, and outflowing jets.

Ammonia spectroscopy offers the opportunity to measure temperatures within the core, thus examining the heating of the core by the embedded source. A program has imaged these same cores in the lines of formaldehyde at 1.3 mm, using the BIMA interferometer. These lines lie at nearly the same energy as the ammonia lines; any difference between the images should stem primarily from chemical differences. Our purpose is to develop millimeter-wavelength probes of temperature and density analogous to ammonia for the higher frequency ranges to be imaged by ALMA. Our first results are mixed. Certainly chemical differences can be important--in the S68N protostar, ammonia shows only modest heating near the young star, while in formaldehyde images, the outflow dominates the protostar’s environment. In IRAS 16293 ammonia shows little near the protostar, while formaldehyde appears to define a miniature ‘hot core’. Observations of L1448 have been obtained which appear to show an intermediate picture. GBT and VLA

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observations of ammonia will be combined to provide complete flux maps in several low-mass dense cores to investigate on smaller scales the structure of temperature and density deduced on larger (0.05 pc) scales from total-power images.

Another excellent probe of cold near-protostellar material is provided by deuterium isotopomers of abundant molecules. Several cores in the Serpens cloud and in NGC 1333 have been mapped at BIMA in a number of isotopomers. We have separated the effects of grain chemistry in the envelope by contrasting emission from deuteroammonia, which may form on grains and be released by energetic events near the protostar, with the deuterated formyl ion, which does not participate in grain chemistry. Interestingly, near the IRAS4A protobinary we find a void of singly deuterated ammonia, a molecule clearly produced in gas-phase chemistry, yet triply deuterated ammonia was recently found at the same position! While this has been attributed to grain-surface chemistry, it is difficult to conceive of a process in which substantial production of singly deuterated ammonia does not accompany the triply deuterated form. The popular grain- surface picture must be incomplete or in error.

+ It is generally held that the N2H molecule is an unbiased probe of dense pre-protostellar cores. + Recently, systematic differentiation of CO, CS, N2H , and NH3 toward a sample of five starless cores in the Taurus region has been observed. The results of these measurements indicate that the abundances of 5 -3 the CO and CS molecules drop dramatically within the denser (n(H2)>10 cm ) regions of these cores, + while the abundances of N2H and NH3 remain flat or increase in these regions. OVRO and VLA + observations of the N2H and NH3 emission toward the cold core containing the low luminosity IRAM 04191 protostar are not consistent with these conclusions. In the even-denser regions of the cores 6 -3 (n(H2)>10 cm ) high resolution is required to study abundance variations. VLA and OVRO results 6 -3 suggest that for densities exceeding n(H2)>10 cm over regions <15 arcseconds in diameter, both + ammonia and N2H are depleted in a similar fashion. This result is important because it suggests that the + only molecular probes observable from the ground of the innermost regions may be H2D (difficult to + observe at 372 GHz) and H3O (equally difficult to detect). We need molecular probes if we are to know the kinematics of these inner regions critical to disk/star/outflow interactions. To this end, measurements obtained at the OVRO Millimeter Array will be used to study a sample of pre-protostellar cores for which + 13 + there have been observations suggesting depletion in the 1-0 transitions of N2H and H CO . These + 6 -3 images of the N2H distribution within cold (<20 K) and dense (n(H2)>10 cm ) regions will clarify the + depletion status of N2H .

The Galactic Center, Pulsars, Novae, Supernovae, X-ray Binaries, and Other Radio Stars

Large-area surveys of the Galactic Center region at 20 and 6 cm will continue using a combination of the VLA and the GBT. These surveys will be combined with existing higher-frequency surveys from the GBT to help separate the thermal from nonthermal components in this complex region of the Galaxy.

The GBT will be used to renew the search for the positronium recombination lines towards the Galactic Center, in particular SgrA East and the Arc. The GBT at 20 and 3.6 cm is more sensitive to spatially extended positronium emission than previous searches which concentrated on possible emission from the compact source SgrA*. It is conjectured that the physical processes responsible for the emission from SgrA East and the Arc lead to a sufficient population of relativistic electrons and positrons. The detection of positronium would verify this hypothesis.

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The clean optics of the GBT makes it a premier instrument for measuring the polarized emission from extended objects. The GBT will undertake a polarization survey of 3 cm and 6 cm continuum emission from the extended Galactic Center Lobe (GCL) north of the Galactic plane. The GCL has been cited as evidence of a mass outflow from the central region of the Milky Way. However, such claims are controversial. The proposed survey will provide the best determination of the nature of the emission from the GCL. The goals are to determine (a) if all the features of the GCL are part of a single coherent structure, (b) the nature of the emission mechanism (thermal, non-thermal), (c) the relationship of the lobe with the immediate environment, and (d) its energetics and its origin.

New 1.3 cm observations of the Galactic Center will be made using the A and B arrays of the VLA. By combining them with data from 1991 and 1997, the proper motions of the ionized gas in the central arcmin near Sgr A* will be determined from images with 0.1 arcsec resolution (0.004 pc or 800 AU). Tracing the trajectories of the motions of the HII components with respect to Sgr A* will provide decisive data for studying the origins of the peculiar motions and will provide clues about the survivial mechanism of young stars near the massive black hole at the center of the Milky Way.

Recent VLBA observations at 7 mm and 1.3 cm have shown that the intrinsic size of Sgr A* is 24 and 72 Schwarzschild radii, respectively. A major challenge is the determination of the appropriate interstellar scattering law (the measured size at 7 mm is 0.712 mas, while the inferred scattering size is 0.669 mas). New observations with the VLA plus the Pie Town link will determine the characteristics of the scattering with unprecedented precison at 18, 20, 22 and 24 cm. These will likely enable measurements of the instrinsic size at wavelengths longer than 1.3 cm.

Pulsar science with the VLA and VLBA continues to make great strides. VLA observations lay the essential groundwork for VLBA astrometry programs through locating suitable calibrator sources and determining initial positions. Additionally, VLA observations are providing proper motions for faint pulsars and revealing the interaction of some pulsars with their associated supernova remnants. A distance to B0656+14 has enabled the pulsar’s radius to be estimated when combined with thermal X-ray data. Additionally, the kinematic properties of pulsars are being probed.

The discovery of the highly relativistic double-pulsar system J0737-3039 has opened up new possibilities for tests of General Relativity and our understanding of neutron-star relativistic winds. NRAO telescopes are part of a concerted multiwavelength campaign (including Chandra, Magellan, and Gemini Adaptive Optics) to investigate the properties of this intriguing system. The VLBA is engaged in an ongoing astrometry program, and the VLA and the GBT will investigate the system flux, its spectral index, and orbital variability.

The GBT and its new pulsar instrumentation (the SPIGOT card and the coherent de-dispersion backends) will be heavily involved in a number of pulsar timing and search projects over the next year. A pilot 350 MHz pulsar survey will pave the way for a potential all-GBT-sky survey with unprecedented sensitivity for “interesting” millisecond and relativistic binary pulsars. Targeted surveys of globular clusters (which are already turning out to be incredibly successful with the GBT) and supernova remnants should continue to uncover new (and exotic) pulsars. Additional work on the scintillation and eclipse properties of the spectacular douple-pulsar J0737-3039 is also scheduled. Several timing projects for binary and millisecond pulsars, both in the field and in clusters, will continue or begin and should yield a variety of science. Finally, as part of the international Pulsar-ALFA collaboration, we will play key roles in the Arecibo multibeam pulsar surveys which are just beginning.

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The orthogonal modes of polarization (OPM) in pulsar radio emission are thought to arise from propagation effects in the pulsar’s magnetospheric plasma. However, the origin of OPM remains uncertain, primarily because observations of mode polarization have been restricted to a narrow frequency range. Multifrequency single-pulse polarization observations of nearby pulsars will be made with the Arecibo radio telescope in an effort to determine the origin of OPM and to investigate how the emission depolarizes at high frequencies.

Previous VLA A-array plus Pie Town observations have shown that the young pulsar B1757-24 is likely not associated with the supernova remnant G5.4-1.2 ( the “Duck”). A new observation will extend the time baseline from 4 to 6 years and reduce the uncertainty in the determination of the proper motion by a factor of 2-3. At this level, a significant proper motion of the pulsar is possible.

The VLA will be used to search for medium-mass black holes in globular clusters. The sensitivity of the VLA at X-band is sufficient to detect emission at the level predicted from models of central black holes in globular clusters.

X-ray observations with RXTE and radio data from the VLA and VLBA will be used to further explore the connections between accretion and relativistic ejection in X-ray binaries. Conditions in the inner accretion flow around collapsed objects such as neutron stars and black holes, accreting from a binary companion, reveal, in coordinated multi-wavelength observations, unexpectedly rich evolution on timescales of milliseconds to months. Specific projects include:

Accretion-disk X-ray spectra, spectral hardness, and power-law index indicate systematic changes in the accretion properties as a function of the AU-scale jet emission imaged by the VLBA. The relationship of X-ray intensity fluctuations (the so-called timing properties) to the radio jet will be further explored by observing the changes surrounding major radio/X-ray flare events.

A VLA monitoring project is expected to continue, providing crucial radio data on X-ray transients for VLBA follow-up imaging. Surprises continue to emerge from this project, including images of superluminal jets, the discovery that in some cases radio emission arises in shells (i.e. spherical shocks) rather than in jets, and the appearance of radio emission at unexpected times and levels from accreting pulsars.

A program is under way using Chandra and the VLA to observe black-hole transients as they return to quiescence. The study of the radio/X-ray relation as a function of mass accretion rate, covering 6 or more orders of magnitude in X-ray luminosity, constrains the models of accretion flow (e.g. ADAFs) and jet production.

The VLA continues to monitor active X-ray binaries, complementing X-ray observations from the Rossi X-ray Timing Explorer, Chandra, and the XMM. Very strong transients are the subjects of follow-up imaging observations with the VLBA and MERLIN, allowing the direct determination of jet speeds and orientations. HI absorption studies (where possible) also constrain source distances.

A program of astrometry on X-ray binaries undertakes to measure their space velocities and Galactocentric orbits based on VLBA proper motions and optical radial velocities. The VLA is also used to filter calibrators for VLBA astrometry. The space velocity relates to questions such as: Do black holes receive a substantial birth kick as do young pulsars? Are very massive black holes formed without going

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through a supernova, and hence expected to be slow moving? Is the binary part of the disk, the bulge, or the halo population?

Astrometry of the young stellar object T Tauri will be performed using the VLBA to yield a highly accurate (error < 1 pc) distance and measure additional acceleration terms due to the binary nature of T Tauri. Also, the distances to 4 other sources in the Taurus cloud will be measured. The VLBA will also be used in a similar way to measure the distances to sources in the Orion nebula.

VLA detections of a number of millisecond X-ray pulsars will be presented. Those detections come as something of a surprise since the X-rays are supposed to come from accretion onto the neutron star surface. The radio emission looks identical to that from other X-ray binaries, a very useful result considering the detailed information available on the accreting pulsars.

Several important sources will be the subjects of intense targeted studies over the coming year. XTE J1748-288 is the only source known in which a continuous, stable radio jet has collided with and been stopped by the interstellar medium; the consequent radio brightening and 90-degree flip of polarization angle will be studied in detail. V404 Cyg, one of the few black holes to be bright enough for detailed study in quiescence, was observed with a number of ground- and space-based instruments this past summer. Those data will be reduced, published, and made public this fall. A similar campaign on the bright neutron-star binary GX 339-4 will also be analyzed. Finally, SS433 remains an interesting and tantalizing source, and detailed analyses of its morphological and polarization properties are under way. In addition to probing the detailed structure of the radio jets, these studies should provide an independent distance estimate and measurements of the jet deceleration.

A radio and optical study of a sample of high-latitude microquasar candidates is under way with the aim of determining whether they are in fact jet sources. The best candidate so far is J1628-41, whose radio and X-ray properties are currently under intense scrutiny. The VLA/VLBA will continue a large program making astrometric measurements of all radio-loud X-ray binaries and X-ray transients. Preliminary results on a number of sources should provide kinematic constraints on source distances and proper motions, essential information for understanding their nature and origin.

In 2005 a coordinated campaign will investigate stellar flares on the active binary system σ Geminorum utilizing an impressive multiwavelength set of telescopes—Chandra, HST, VLA, MERLIN, and VLBA. These observations will be used to explore spectroscopically (HST and Chandra) the dynamics of flaring plasma, the change in the characteristics of the nonthermal electrons (VLA, MERLIN) through changes in their continuum spectra, and the large-scale magnetic volume involved in the flare through changes in the VLBA source size with time and activity. Parallels with a multi-wavelength analysis of a past campaign on a similar active star (UX Arietis; coordinated VLBA, VLA and serendipitous EUVE observations) will be performed to investigate trends in flaring characteristics.

The discovery of radio emission from brown dwarfs a few years ago has piqued astronomers’ interests in the atmospheres of these ultracool objects. Two unknowns are: (1) the emission mechanism(s) responsible for the observed steady and flaring radio emission, and (2) the frequency of brown-dwarf radio emission. Current understanding of brown-dwarf atmospheres suggests that they are highly neutral and unable to sustain large magnetic stresses; thus it is puzzling that such large flux densities (up to 1 mJy) are observed at high frequencies (8 GHz), which would normally require either large ambient densities or large magnetic field strengths. Recently, a sensitive multi-frequency VLA observation of a previously detected brown dwarf (spectral type M9) revealed continuum spectra consistent with patterns

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seen in earlier M dwarfs. In the next year, deep multi-frequency observations of a sample of brown dwarfs over a range of spectral types, having single-frequency detections, will be performed to explore the ubiquity of this trend. The VLA is currently performing a volume-limited survey of radio emission from nearby (out to 13 pc) brown dwarfs to determine the frequency with which brown dwarfs exhibit radio emission. Such measurements are crucial to connect radio behavior with trends of both chromospheric and coronal activity in ultracool objects. In 2005 reduction and analysis of the data will be performed, and correlations with chromospheric activity and trends in stellar properties will be examined. Archival analysis of a large volume-limited survey of M dwarfs carried out from 1986-1992 will make statistical comparisons with the newly obtained results from L and T dwarfs. The connection between coronal activity measured by radio fluxes and coronal activity diagnosed by X-ray emission will also be investigated. Chandra and the VLA will observe a nearby L dwarf Kelu-1, allowing for an investigation of the X-ray and radio properties of this brown dwarf.

One of the multi-wavelength trends seen in active stars is a correlation between time-averaged X-ray and radio luminosities extending over 8 orders of magnitude (e.g. Drake et al. 1989, Benz & Gudel 1994). A convincing explanation has not been proffered for this correlation, and renewed interest in the underlying causes of the correlation have arisen in the past few years as newly discovered types of stellar sources appear to violate the correlation (e.g. the radio luminosities of brown dwarfs can be up to 10,000 times that predicted from the LX - LR correlation). The GBI surveyed several active stars, with an overlap in time with the Rossi X-ray Timing Explorer (RXTE) in 1996-2000. Three active binary systems were observed by both telescopes, and a statistical investigation of the X-ray and radio luminosities is exploring (1) the correlation of X-ray and radio luminosities and (2) the statistics of multi-wavelength flaring for large radio and large X-ray flares. Initial results suggest that the linear LX - LR relation suggested by Drake et al. (1989) and Benz & Gudel (1994) does not hold for each star at various activity levels, and that large radio and X-ray flares generally show a poor temporal correlation.

The influence of magnetic fields on the formation and further evolution of late-type stars is both profound and poorly understood. Among several classes of active stars and solar flares, a tight relation is found between X-ray and radio luminosities. This relation, which implies an intimate physical connection, has been subject to coordinated radio and X-ray studies for particular active binaries and dMe stars, but never among one of the most active classes of stars, pre-main sequence stars. In 2005 a pair of coordinated VLA and Chandra observations of the nearby young cluster around LkHα101 will examine the X-ray/radio connection simultaneously for several scores of stars. The data will tighten the relation for the quiescent emission and study the causal connection between radio and X-ray flares for young stars with and without disks. A key question is the extent to which magnetic dynamos in the stellar interior, or some mechanism associated with the presence of a disk, controls the magnetic field topology and regulates magnetic activity. The role of keV (through X-ray variability) and MeV (through radio variability) particles in regulating the disk can be investigated by comparing statistics of luminosity/variability of stars with and without disks.

The VLA will observe a sample of historical supernovae to check for high-frequency emission similar to that seen in supernova 1986J. Such emission may be the first signature of a compact remnant (black hole or neutron star) born in the original explosion. Supernova 1986J will itself be the subject of further VLA and VLBA studies, concentrating on the high- frequency emission unexpectedly found in its core. Radio “light curves” from the VLA will clarify the relation between this emission and that from the expanding shock front, while VLBA images will further constrain its size and morphology. The VLBA imaging is intended (1) to follow the changing deceleration of the remnant; (2) to make images of the evolving spectral index distribution; and (3) to monitor changes in the overall morphology, with particular interest

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in the development of Rayleigh-Taylor and other instabilities. Comparison with hydrodynamic simulations and on-going Chandra (X-ray) observations should yield further insights into the detailed behavior of young supernova shocks.

The VLA will be used to study radio emission from extragalactic supernovae. Typically, supernovae are discovered optically, and rapid follow-up observations at X-ray, UV, optical and radio wavelengths are used to study the evolution of the supernova ejecta and, indirectly, to understand the explosion and the last moments of the life of a star. The radio observations are unique and valuable in that they probe the stellar wind of the star for the last few thousand years before the explosion.

The Solar System and other Planetary Systems

Radio observations of the Sun provide important insights into a wide variety of physical processes in the solar atmosphere, including the structure and dynamics of the solar chromosphere and corona, coronal magnetic fields, and transient energetic phenomena such as flares, radio bursts, and coronal mass ejections. Radio observations also play an important role in probing the outer corona and the inner heliosphere. A number of radio diagnostics based on propagation phenomena—e.g., angular broadening and interplanetary scintillations—have been exploited to constrain the nature of the turbulent solar wind. VLA observations have played a prominent role in all of these areas in past years and will continue to do so as the VLA transitions to the EVLA. The VLA also played a prominent role in multiwavelength studies of the Sun with ground-based optical telescopes and NASA missions such as the SMM, CGRO, Yohkoh, SOHO, TRACE, missions, and now the RHESSI mission.

In recent months, as the Sun declines from maximum to minimum activity levels, the research focus has turned from energetic phenomena to the quiet Sun. An outstanding problem is the structure and dynamics of the solar chromosphere. Most past models of the chromosphere are semi-empirical and static, using UV/EUV line and continuum and infrared/mm continuum observations. However, it has been recognized for some time that the chromosphere is a dynamic entity, continuously perturbed from below by acoustic waves. These shock as they propagate into the chromosphere, affecting the temperature and ionization of the chromospheric plasma. Complicating matters is the presence of the network magnetic field. Recently, dynamic models have been constructed and have achieved consistency with non-LTE UV/EUV observations. Interestingly, these models imply a significantly cooler chromosphere than is inferred from static models. Dynamic models of the chromosphere make several predictions about the nature of brightness-temperature variations at submm, mm, and cm wavelengths. Recent observations made at the VLA, supported by ground-based observations in the Ca II K line and TRACE observations in the EUV, are designed to address the problem of the dynamic chromosphere. These will be analyzed in detail in the coming year.

Passive radio observations of solar-system objects allow properties of their atmospheres, surfaces, and magnetic fields to be inferred. Active radio observations (radar) allow additional properties of surfaces and magnetic fields to be inferred, and can also give insights into the spin state of the probed body. Radio wavelengths are unique in their ability to probe into regions inaccessible to shorter wavelengths, e.g., into the deep atmospheres and into the subsurfaces of planets. They are also unique in their ability to observe in conditions which would make shorter-wavelength observations useless (daylight, cloud cover, etc.). They have therefore made, and continue to make, very important contributions to planetary astronomy and planetary science in general.

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Radar observations of Mars provide important constraints on the surface and subsurface properties, including structure (or “texture”). The combination of the Goldstone transmitter and the VLA provides a powerful direct-mapping bistatic radar instrument which has been used successfully during the oppositions of 1988, 1992/93, and 1999 to make radar reflectivity maps of the planet. The opposition of 2003 was a fantastic opportunity to continue the successful Goldstone/VLA experiments in this respect. Questions regarding the differences between the south and north ice caps, “Stealth” regions, the Hellas basin, and other interesting areas on the planet can be addressed with data taken during this opposition. The 2003 Mars opposition also provided an excellent opportunity to once again observe the tenuous water vapor in its atmosphere with the VLA. Reduction of this data will continue - in final form it will be used to constrain the amount and vertical distribution of water vapor in the atmosphere of Mars as a function of time.

Radio observations of Uranus provide important information on the deep atmosphere, including temperature and abundance (notably of ammonia, the major variable contributor to opacity at these longer wavelengths). Observations during the next few years will be especially important, as the planet is approaching equinox. In 2007 its north pole will emerge into sunlight for the first time in 42 years. Observations of the deep atmosphere are critical for deducing the dynamics of the deep (and shallow) atmosphere. A program of VLA observations of the planet (during every A configuration) will continue.

With the Cassini spacecraft approaching the Saturn system, observations of that planet and its moons are especially important during the next few years. In particular, its largest moon Titan is one of the more enigmatic bodies in the solar system. VLA observations of Titan in the upcoming VLA A configuration will be used to constrain the atmospheric and surface properties of this large icy satellite.

The larger asteroids are the only surviving protoplanets from the early solar system. Understanding their properties and the differences between the bodies is a key to unraveling the history of the solar system. Radio-wavelength observations can be used to determine the depth of the regolith layer on these bodies and how it varies across them. This can be used in turn to place constraints on the collisional histories of the bodies. Observations of Ceres, Pallas, and Vesta during the upcoming A configuration of the VLA will be used to make such determinations.

Astrometry

Six 24-hour VLBA observations per year are devoted to improving the International Celestial Reference Frame (ICRF) catalog at 8 GHz. These observations are led by GSFC and USNO, with NRAO participation The present accuracy of the frame is 0.03 mas. For spacecraft tracking at 33 GHz, the ICRF catalog must be determined at this frequency in order to measure the accurate spacecraft positions with respect to the background quasars. A group at JPL, USNO, GSFC and NRAO have already made six VLBA observations at 22 GHz and 43 GHz to establish this high-frequency quasar grid.

Three 24-hour VLBA observations have been made to increase the density of VLBA calibrators for use in phase referencing. Regions near the Galactic plane south of -20 deg declination, and filling holes in the sky larger than four degrees has been emphasized.

VLBA observations of spacecraft at 8 GHz have been made in order to demonstrate to JPL the feasibility of a long-term project to track spacecraft for NASA’s planetary space missions over the next decade. Observational accuracy of 0.3 mas has been obtained from analysis of the VLBA results by the JPL

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navigation team. The expected Mars missions in 2007 will use a telemetry frequency of 33 GHz; hence upgrading the VLBA to this frequency with wideband receivers is under investigation.

In order to obtain the highest positional accuracy, more than one calibrator can be used to remove long- term tropospheric delay errors. Positional errors decrease from about 30 microasec to 10 microasec and image dynamic ranges improve from 30:1 to 100:1. Software in AIPS is now available for routine reductions of multi-calibrator observations.

Instrumentation

A new instrument, the Green Bank Solar Radio Burst Spectrometer (GB/SRBS), was successfully deployed in January, 2004. The instrument is a swept-requency spectrometer operating from 18 to 70 MHz and produces dynamic spectra of solar radio bursts during daylight hours. The instrument is the result of a collaboration among the NRAO, the NRL, and the University of Maryland. The instrument is designed to fill a gap in spectroscopic coverage for solar and space-weather studies that previously existed in the western hemisphere. Data from this instrument are readily accessible by the public through a web-based interface.

In the coming year the GB/SRBS will undergo a significant upgrade. New amplifier-baluns and antennas have been developed which expand the low-frequency coverage of the instrument to 10-300 MHz. Moreover, the 45 ft telescope at Green Bank will be used to support spectroscopy from 250-800 MHz using a Swiss-built (ETH/Zurich) spectrometer. Hence, continuous spectral coverage from 10-800 MHz will be available in 2005. The instrument is also playing an important role as a development platform for FASR. In particular, ultra-wideband amplifiers and feed structures will be designed and tested, and signal-processing strategies are being explored. The final configuration of the spectrometer may extend the frequency coverage to 3 GHz.

As part of a new education initiative, selected graduate students will be given a unique opportunity to work together with researchers from the science and engineering disciplines within NRAO and abroad on projects that blend cutting-edge scientific research with advanced instrument development. These projects were carefully designed to foster an atmosphere of collaboration among researchers having diverse backgrounds while introducing students to the techniques of successful project management and teamwork. Students will be engaged in project activities such as instrument design, construction, deployment, calibration, observation, and analysis at levels commensurate with their abilities. The following projects will be underway in the coming year: (1) a collaboration with the Radio Astronomy Laboratory at Berkeley to conduct a study of the time-variability of the sky at 150 MHz in preparation for a systematic search for the epoch of reionization signature, (2) a collaboration with the Naval Research Laboratory to search for the radio Cerenkov radiation from high-energy neutrinos which may interact with the lunar regolith, and (3) a project to carry out a careful study of the various contributions to the noise temperature of the current GBT L-band receiver and develop a new receiver concept that will approach the theoretical limit for sensitivity on this telescope.

There will be a continued development of techniques for high-frequency single-dish imaging with the GBT Penn Array camera. This instrument is expected to be commissioned in the coming year.

Continued development of low frequency (74 MHz) interferometric calibration and imaging techniques are anticipated. These techniques are needed for optimizing the scientific results from the current VLA

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74 MHz system and are critical for the Low Frequency Array (LWA) now being considered in the U.S. Southwest. Techniques for ultra-sensitive, wide-field imaging with synthesis radio telescopes such as the Expanded Very Large Array and Square Kilometer Array will be developed.

The application of Bayesian Markov Chain Monte-Carlo sampling to image analysis and image deconvolution will be investigated with special regard to accurate component fitting.

The two new algorithms for atmospheric correction have been designed and implemented in AIPS. The algorithms allow the user to improve image quality and the accuracy of coordinate measurements for astrometric purposes.

The standardization of FITS nomenclature for spectroscopy will be completed in the coming year. This will assist in setting standards for describing instrumental nonlinearities which affect world coordinates.

Detailed 3-D simulations of atmospheric turbulence will be carried out. The goal of these simulations is to establish an optimal strategy for combining water-vapor radiometry and fast-switching phase calibration in the context of ALMA. A large survey to search for ALMA calibrators at 90 GHz will be executed.

Efficient algorithms to correct for various image-plane effects which limit the dynamic range of mosaic observations will be developed. This will include dealing with the issues of high-performance computing required to handle the large data rates from the new telescopes that we anticipate in the next few years.

Algorithm development for imaging with ALMA and the EVLA will be considered. The algorithms that will be worked on over the next year will include mosaicing and image-plane error estimation and correction.

New imaging techniques for the processing of high-precision full-beam and multi-field mosiac data in full polarization will be developed, e.g. for use with ALMA, the EVLA, and the GBT as well as other community instruments.

Development of new algorithms for post-correlation identification and removal of RFI will continue.

Testing of the new wide-band, high-sensitivity receivers for the EVLA project will continue through the year. These receivers are part of the EVLA goal to provide complete frequency coverage between 1 and 50 GHz.

A new MRI grant will fund the implementation of blanking and adaptive-filter RFI mitigation algorithms on NRAO telescopes using FPGA technology, and new mitigation techniques will continue to be developed in collaboration with BYU EE faculty and students. RFI data- acquisition and monitoring instrumentation will continue to be upgraded.

The component technologies necessary for the construction of high-sensitivity phased-array feeds (small- scale cryogenics, LNA/antenna integration, reduction in size and weight of IF electronics, high-speed digital signal transmission, etc.) will continue to be developed in the coming year. These technologies will have short-term benefits to the GBT as incremental enhancements to the current receiver system.

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A new 26-40 GHz receiver will be fully commissioned on the GBT in the fall of 2004. This receiver is suitable for general spectroscopic and continuum use with existing GBT backends. Initial tests of the receiver were conducted on the GBT in the spring of 2004. In addition a fast-switching continuum backend (the Caltech Continuum Backend or CCB) will be commissioned late in 2004 or early in 2005. This backend will simultaneously detect power from both polarizations of both feeds over the entire receiver band. Both the new 26-40 GHz receiver and the CCB will be available as user instruments. The Ka-band receiver, in conjunction with the CCB and the GBT’s present 30 GHz aperture efficiency, will provide a preeminent cm-wave continuum capability.

Observations with the current VLA and VLBA are being used to study calibration techniques which will be necessary for the EVLA and ALMA. In particular, a proper treatment of instrumental polarization calibration (rarely required for the current instruments) will be necessary to minimize the associated closure errors and reach the dynamic range (for bright sources) implied by the projected EVLA sensitivity, even in total intensity (not just polarization imaging). This problem is exacerbated by the fact that the instrumental polarization is frequency-dependent, so the greater EVLA sensitivity (achieved primarily via wider bandwidths) is not easily leveraged to improve this calibration.

A VLBA Spacecraft Navigation Pilot Project, inaugurated in September 2003, will study the feasibility of using the VLBA to provide critical inputs for spacecraft navigation. Using phase-referencing (now a common, standard VLBA observing mode) it should be possible to obtain high-precision coordinates of spacecraft downlink transmitters. These two-dimensional measurements, orthogonal to the range measurements which are the basis of conventional spacecraft navigation, should significantly enhance the determination of spacecraft orbits. The Pilot Project will also compile requirements and cost estimates for upgrading VLBA instrumentation in order to make such observations possible on a routine basis with minimal interference with the VLBA’s ongoing scientific programs.

The band 780-950 GHz is ALMA’s Band 10. At present no receivers for this band can achieve the nearly quantum-limited sensitivity of niobium SIS receivers below ~ 600 GHz. It is therefore appropriate for NRAO to develop the technology for quantum-limited receivers in Band 10. The goal is to develop reliable, inexpensive, quantum-limited receivers based on NbTiN SIS mixer technology which has given promising, though not yet consistent, results in other laboratories. The mixers will be designed to support a wide IF bandwidth, as required by ALMA, and in a form suitable for sideband-separating mixers which are desirable for ALMA. Success in this work will put NRAO in a strong position to bid on the ALMA Band 10 receiver production. This work will be done in collaboration with the Microfabrication Laboratory at the University of Virginia with whom the NRAO has an established record of successful development, including SIS receivers for the 12-m telescope and, more recently, for ALMA. In 2004 the University of Virginia purchased major fabrication equipment which puts them in a position to start work immediately on NbTiN/AlN/Nb circuits.

New-generation submillimeter-wave mixer-circuit technology will be developed. In particular, the development of the beam-lead quartz chip technology for superconducting millimeter-wave circuits will continue. A 385-500 GHz SIS mixer using the University of Virginia’s new 7 micron-thick Silicon on Insulator (SOI) wafer technology will be used to demonstrate the feasibility of using SOI technology in fabricating submillimeter-wave circuits. The new mixer design, if successful, can also be used as the prototype design for the future ALMA Band 8 mixer. This 385-500 GHz SIS mixer development project is a joint R&D effort between the NRAO and the University of Virginia, and it is supported mainly by an NSF grant to the University of Virginia.

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Work on frequency-multiplier design/prototyping for the LO system to support the requirement for ALMA Bands 4, 8 and 10 will begin. These multipliers are required to cover the frequency ranges of 133 - 155 GHz, 393 - 492 GHz, and 795 - 942 GHz, respectively. These designs (particularly the high- frequency ones) push the state-of-the-art in frequency multiplier technology and require unique design and fabrication techniques and processes.

The NRAO is pursuing the development of submillimeter-wave and terahertz receiver components, leveraging its expertise in low-noise microwave and millimeter-wave receiver systems. A project to develop a THz Ortho-Mode Transducer is the first step in a program to develop high-frequency integrated receiver systems for use on future ground- and space-based platforms.

New Monolithic Millimeter-wave Integrated Circuits (MMICs) and MMIC-based Multi-Chip Modules (MCMs) for use in the next generation of millimeter-wave receivers will be developed. MMICs provide highly repeatable performance in a more compact package than traditional millimeter-wave assemblies, and at lower cost in large quantities. This dramatically improves the tradeoff between cost and performance in array architectures. This is applicable to large interferometers such as the EVLA and ALMA, as well as to array feeds for single-dish telescopes like the GBT.

Future MMIC designs planned include LNAs, power amplifiers, mixers, frequency multipliers, switches, and variable attenuators. These are targeted for many projects, including the EVLA, ALMA (to improve present bands as well as support future frequency bands), the Deep Space Network (in collaboration with JPL), and the SKA. Highly integrated MMIC-based modules are also planned, including Compact Water- apor Radiometers (CWVRs) for the EVLA, and Active Multiplier Chains and Power-Amplifier modules for future ALMA LO bands.

Several projects jointly funded by the NSF and the Intelligence Community under the Approaches to Combat Terrorism (ACT) program will continue. Hot-electron bolometer (HEB) receivers are being developed for potential use in THz biohazard spectroscopy, THz imaging, and future supra-THz ALMA receiver upgrades. Using a new beam-lead HEB process developed at the University of Virginia, both phonon-cooled and diffusion-cooled HEB mixers are being characterized in a 600-700 GHz receiver at the NRAO. HEB mixers fabricated on different substrates and with different fabrication procedures are also being characterized in the same receiver. Based on insights gained from these studies, HEB receivers will be designed for 1.3-THz operation.

Work will continue to model the noise of InGaAs/InP HFET’s with emphasis on fundamental limitations and experimentally demonstrated lack of repeatability of performance for different wafers at cryogenic temperatures. This work is intended to address the connection between what is now known as the Pospieszalski FET/HFET noise model and the physics of these devices. We hope to explain the experimentally observed anomalies in noise/performance of InP HFETs at low microwave frequencies (around 1 GHz), the 1/f noise in HFET’s, and its influence on radiometer properties.

Developing the noise theory of Heterostructure Bipolar Transistors (especially InP) with emphasis on fundamental limitations is an additional project planned for 2005.

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The Penn Array Receiver (PAR), a 64-pixel bolometer array operating in the 86 to 94 GHz range, will be tested on the GBT in early 2005. The PAR receiver uses Transition Edge Superconducting (TES) bolometers and closed-cycle cryogenics. These technologies are suitable for possible very large bolometer arrays in the future. Continuum-imaging algorithms for the PAR will also be tested and implemented. The PAR will be available as a user instrument at a later date.

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Appendix B

Research Staff

D. S. Balser - Galactic structure and abundances, H II regions, and planetary nebulae; GBT scientific support. T. S. Bastian - Solar/stellar radiophysics, flares, coronal mass ejections, solar chromosphere, radio propagation in the interplanetary medium; radio interferometry; Frequency Agile Solar Radio telescope (FASR) planning; grad student support. J. M. Benson - Extragalactic radio sources, pulsar astrometry; VLBA image processing, scientific support for VLA/VLBA correlator and real-time software development. S. Bhatnagar - Supernova remnants, HII/UCHII regions, low frequency mapping of the Galactic plane, interferometric calibration and image reconstruction and related algorithm development; AIPS++. R. C. Bignell - Planetary Nebula, polarization; GBT Scheduling. J. Braatz - Masers, active galactic nuclei and cosmology; scientific software development. R. F. Bradley - Millimeter electronics, low-noise amplifiers, array receivers, adaptive RFI excision; advanced receiver development. A. H. Bridle - Extragalactic radio sources; CIS scientific support. W. Brisken - Pulsars, astrometry, disk-based VLBI. E. W. Bryerton - Millimeter-wave receiver development and HEB mixer research; ALMA local oscillator development. B. J. Butler - Planetary astronomy; EVLA Project Software Scientist. C. Carilli - Galaxy formation, radio galaxies, QSO absorption lines, epoch of reionization; VLA support, ALMA planning, SKA planning. C. Chandler - Star formation, circumstellar disks, protostellar outflows, millimeter-wave interferometry; VLA scientific support. S. Chatterjee - Multi-wavelength investigations of neutron stars, their distances, velocities, and relativistic winds; with an emphasis on high-precision VLBA astrometry, which yields accurate parallax distances to radio pulsars; Jansky Fellow. T. C. Cheung - Multi-frequency studies of jets in AGN; VLBI polarimetry; Jansky Fellow. B. G. Clark - EVLA control and software development; VLA/VLBA scheduling. M. J. Claussen - Masers, young stellar objects, AGB stars, protoplanetary nebulae, spectropolarimetry; VLA and VLBA User Programs, VLA+Pt link support, VLA and VLBA scientific support. J. J. Condon - Nearby galaxies, evolution of star formation, radio surveys; Project Scientist, GBT precision telescope control system; Interim Deputy Director. T. J. Cornwell - Interferometry, image reconstruction methods, coherence theory, and radio source scintillation. W. D. Cotton - Extragalactic radio sources, interferometry, computational techniques for data analysis; scientific support: NRAO sky surveys and VLBI. Radio and IR interferometric observations of AGB stars. V. Dhawan - Radio and X-ray observations of microquasars; VLBA astrometry, VLBA millimeter-wave support. D. T. Emerson - Nearby galaxies, millimeter-wave instrumentation and research into the history of microwaves; NA ALMA Technical Advisory Committee Chair; Observatory Technical Council; Spectrum Management. V. Fish - Masers, high-mass star formation; Jansky Fellow. J. R. Fisher - Cosmology, signal processing, and antenna design; advanced receiver development. E. B. Fomalont - Astrometry, X-ray binaries, deep imaging, relativity tests, VSOP and RadioAstron coordination, VLBA support, AIPS++ testing.

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Appendix B

D. A. Frail - Gamma-ray bursts, soft gamma ray repeaters, pulsar/supernova remnant associations, pulsar wind nebulae, masers, HI absorption and interstellar scattering. F. D. Ghigo - X-ray binaries, AGNs, interacting galaxies; GBT scientific support (VLBI). K. Golap - Wide-field low-frequency imaging; AIPS++. W. M. Goss - Galactic Center studies, Galactic Masers, pulsars, supernova remnants and nearby galaxies; Head of Division of Science and Academic Affairs. E. W. Greisen - ISM structure and computer analysis of astronomical data; AIPS Group. C. E. Groppi - Protostellar/protoplanetary accretion disks, molecular outflows, molecular cloud structure, submillimeter and terahertz technology development, heterodyne array receivers, applications of micromachining, ALMA front-end development; Jansky Fellow. E. J. Hardy - Cosmology, galaxies, and stellar populations; NRAO/AUI representative in Chile. J. E. Hibbard - Extragalactic HI, galaxy evolution and merging galaxies; spectral synthesis imaging; NA ALMA Science Center. D. E. Hogg - Radio stars and stellar winds, and extragalactic HI; general support for the Director's Office. M. A. Holdaway - Imaging methods, mosaicing, calibration, tropospheric transmission, site testing, simulations, operational optimization, ALMA. P. R. Jewell - Interstellar molecules, molecular spectroscopy; Assistant Director, Green Bank Operations. N. Kanekar - Galaxy formation, damped Lyman-alpha systems, OH megamasers, structure of the ISM, the evolution of fundamental constants; Jansky Fellow K. I. Kellermann - Radio galaxies, quasars, cosmology, and radio telescopes. A. R. Kerr - Millimeter-wave receiver development; SIS mixer design - ALMA. L. Kogan - Maser radio sources; theory of interferometry; design of array configurations; AIPS group. Y. Y. Kovalev - Extragalactic radio sources, single-dish and VLBI; Jansky Fellow. G. I. Langston - Gravitational lenses, galactic plane transient surveys and searches for extra-solar planets; GBT scientific support. H. S. Liszt - Molecular lines, millimeter wave absorption line spectroscopy, diffuse clouds, the galactic center and galactic structure; manager of NRAO’s foreign telescope travel support program, and director of NRAO’s spectrum management activities. K. Y. Lo - Galactic Center, star formation in dwarf galaxies, star-burst galaxies and high redshift galaxies, mega-masers and AGN, intergalactic medium, microwave background radiation, millimeter- and submillimeter-wave interferometry; Director. F. J. Lockman - Galactic structure, interstellar medium, and H II regions; GB education and outreach, GBT scientific support. J. P. Macquart - Interstellar scintillation, structure of the ISM, Intra-day variability, AGN polarization and structure, gravitational radiation; Jansky Fellow. R. J. Maddalena - Molecular clouds, galactic structure, interstellar medium; GBT scientific support. J. G. Mangum - Star formation, astrochemistry, and molecular spectroscopy of comets; ALMA. B. S. Mason - Cosmology & cosmic microwave background; high frequency instrumentation development for the GBT. M. M. McKinnon - Pulsar astrophysics, radio polarimetry, statistics; Deputy Assistant Director, New Mexico Operations. J. P. McMullin - Star formation, interstellar medium, astronomical software systems; IPT Lead AIPS++. N. Miller - Clusters of galaxies, multiwavelength studies of galaxy evolution; Jansky Fellow. A. H. Minter - Interstellar turbulence and galactic HI; GBT scientific support. A. J. Mioduszewski - Microquasars, symbiotic stars, modeling of supernovae; AIPS and VLBA support. G. Moellenbrock - Blazars, polarization interferometry and VLBI techniques, calibration and imaging software; VLBA user support.

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Appendix B

M. Morgan - Millimeter-wave MMIC design, MMIc-based instrumentation, arrays, receiver component development for EVLA, GBT, ALMA, and SKA. S. Myers - Cosmology, cosmic background radiation, gravitational lenses, astronomical imaging; AIPS++ Project Scientist, ALMA and VLA/EVLA scientific support. P. J. Napier - Antenna and instrumentation systems for radio astronomy; EVLA Project Manager. K. O’Neil - Extragalactic gas and dust; low surface brightness galaxies; GBT spectrometer; GBT scientific support. R. A. Osten - Stellar coronae, stellar flares, multi-wavelength observations of flares, stellar radio emission, flaring in very low mass stars/brown dwarfs, interrelationship of radio/soft X-ray stellar emissions; Jansky Fellow. F. N. Owen - Clusters of galaxies, radio galaxies, deep continuum surveys; EVLA. S. K. Pan - Superconducting millimeter and sub-millimeter wave low-noise devices, circuits and receivers development; Central Development Lab. J. M. Payne - Telescope optics, millimeter-wave receivers, metrology systems, and cryogenic systems; local oscillator development - ALMA. R. A. Perley - Radio galaxies, QSOs, and interferometer techniques; EVLA Project Scientist. M. Pospieszalski - Microwave and millimeter wave low-noise devices, circuits and receivers; CMBR radiometers; EVLA/VLBA/GBT/ALMA receiver development support. R. Prestage - Telescope performance and control; Project Manager, GBT Precision Telescope Control System; Deputy Assistant Director, Green Bank Operations. S. J. E. Radford - Starburst galaxies and millimeter interferometry; ALMA site characterization, ALMA site development. S. M. Ransom - Pulsar searches and timing (especially binary and millisecond pulsars); GBT pulsar infrastructure improvement. J. D. Romney - Active galactic nuclei, interstellar medium, VLBI instrumentation; VLBA scientific support, VLBA upgrade planning, VLBA Spacecraft Navigation Pilot Project manager. M. P. Rupen - X-ray binaries and transient sources; supernovae; interstellar medium; VLA and EVLA scientific support; research leave. K. Saini - ALMA local oscillator development, frequency multiplier development. H. R. Schmitt - Active galactic nuclei, starburst galaxies; Jansky Fellow. D. S. Shepherd - Star formation; molecular outflows; disks around luminous young stellar objects; molecular chemistry; millimeter interferometry and mosaic techniques. Y. Shirley - Star formation, astrochemistry, protostellar disks, and molecular spectroscopy; Jansky Fellow. L. O. Sjouwerman - Circumstellar masers and AGB stars, centers of the Galaxy and Andromeda, VLBA data calibration and logistics, VLA/VLBA scientific support R. A. Sramek - Normal galaxies, quasars, supernovae, and aperture synthesis techniques; ALMA. G. B. Taylor - Gamma-ray bursts, active galactic nuclei and their environments, polarimetry; Head of Scientific Services Division - Socorro Operations. B. E. Turner - Galactic and extragalactic interstellar molecules, interstellar chemistry, and galactic structure; ALMA scientific support. J. S. Ulvestad - Seyfert, LINER, and starburst galaxies, and extragalactic gamma-ray sources; Assistant Director, New Mexico Operations. J. M. Uson - Clusters of galaxies and cosmology, superthin galaxies, dark matter; Spectral synthesis imaging. P. A. Vanden Bout - Interstellar medium, molecular clouds, and star formation; Head of NAASC. G. A. van Moorsel - Dynamics of galaxies and groups of galaxies, and techniques for image analysis; Head, EVLA Computing. R. C. Walker - Extragalactic radio sources, VLBI, and VLBA development; VLBA scientific support.

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Appendix B

H. A. Wootten - Star formation, structure and chemistry of the ISM in galaxies, and circumstellar material; ALMA Project Scientist. J. M. Wrobel - active galactic nuclei, sky patches at milliarcsecond resolution; VLA/VLBA scheduling, GBT student support coordinator. Q. F. Yin - Normal galaxies and imaging techniques; NRAO sky surveys.

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Appendix C

Management Staff

Adams, Mark - Assistant to the Director Anderson Jr., Robert – Green Bank Telescope Operations Division Head Beverage, Charles - Management Information Systems Manager Bolyard, Jody - Safety & Environmental Protection Manager Clark, Christopher – Green Bank Computing Division Head Condon, Jim - Interim Deputy Director, Scientist D'Angio, Robert - Human Resources Manager Delgado, John - Procurement and Contracts Manager Durand , Steven - Socorro Electronic Division Head Egan ,Dennis - GB Mechanical Engineering Division Head Ford, John - GB Electronics Division Head Gasho, Victor - ALMA Antenna Division Head Gibb, James - Fiscal Officer Glendenning, Brian - ALMA Computing Division Head, Scientist Golap, Kumar - Science Software Group Deputy Project Manager, Associate Scientist Goss, W. Miller - Head of Division of Science and Academic Affairs, Scientist Hardy, Eduardo - NRAO/AUI representative in Chile Holstine, Michael – Green Bank Business Manager Hubbard, David - Head of Observatory Program Office Hunt, Gareth - Head of Computing and Information Systems, Scientist Janes Clinton - ALMA Backend Division Head Jewell, Philip - Assistant Director Green Bank Operations, Scientist Kellermann, Ken - Head of New Initiatives, Scientist Lagoyda, Skip - Socorro Business Manager Lo, K.Y. - Director, Sr. Scientist McKinnon, Mark - Deputy Assistant Director New Mexico Operations, Scientist Miller, Theodore - Head of Observatory Business Services McMullin, Joe - Science Software Group Project Manager, Scientist Murphy, Patrick - Charlottesville Computing Division Head Napier, Peter - EVLA Project Manager, Scientist Norville, Roy - Deputy Human Resources Manager Payne, John - Head of ALMA Front End, Scientist Perfetto, Antonio - ALMA Frontend Deputy Division Head Perley, Margaret - Socorro Array Operations Division Head Pilleux, Mauricio - Chili Business Manager Porter, William - ALMA Business Manager Prestage, Richard - Deputy Assistant Director Green Bank Operations, Scientist Radziwill, Nicole - GB Software Development Division Head Rafal, Marc - NA ALMA Deputy Project Manager Robnett, James - Socorro Computing Infrasture Division Head Russell, Adrian - North American ALMA Project Manager Serna, Lewis - Socorro Engineering Services Division Head Shapiro, Lee - Head of Education and Public Outreach Simon, Richard - ALMA JAO Project Controller, Scientist Sramek, Richard - Deputy Assistant Director ALMA, Scientist

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Appendix C

Thunborg, Jon - Socorro Engineering Services Deputy Division Head Ulvestad, James - Assistant Director New Mexico Operations, Scientist Vanden Bout, Paul - Head of North American ALMA Science Center, Sr. Scientist Webb, Dale - Tucson Business Manager Webber, John - Head of Central Development Lab, Assistant Director, Scientist Wootten, Al - ALMA Science IPT Leader, Scientist

NRAO Program Plan ♦ FY2005 208

Appendix D

Committees

The Users Committee

The Users Committee is made up of users and potential users of NRAO facilities from throughout the scientific community. It advises the Director and the Observatory staff on all aspects of Observatory activities that affect the users of the telescopes. This committee, which is appointed by the Director, meets annually in May or June. The current membership of the Committee is:

Robert Becker University of California, Davis Geoffrey Bower University of California, Berkeley Jeremiah Darling Carnegie Observatory John M. Dickey University of Minnesota Sean M. Dougherty Dominion Radio Astrophysical Observatory Gary Fuller U. of Manchester Institute of Science & Tech Bryan Gaensler Harvard University Mark Gurwell Smithsonian Astrophysical Observatory Deborah B. Haarsma Calvin College Andrew I. Harris University of Maryland Deidre Ann Hunter Lowell Observatory Victoria M. Kaspi McGill University Henry Kobulnicky University of Wyoming Stanly Kurtz UNAM Cornelia Lang University of Iowa Kevin B. Marvel American Astronomical Society Mary Putman CASA University of Colorado Michele Thornley Bucknell University Stephen E. Thorsett University of California, Santa Cruz Edward Wollack NASA GSFC Min Yun University of Massachusetts Liese van Zee Indiana University

The Program Advisory Committee

The Program Advisory Committee reviews and provides advice on the long range plan of the Observatory, on new programs and projects being considered for implementation, and on the priorities among Observatory program elements. Current membership of the Committee is:

Donald Backer University of California, Berkeley James M. Cordes Cornell University Lee Mundy University of Maryland Mark Reid Center for Astrophysics Lawrence Rudnick University of Minnesota F. Peter Schloerb University of Massachusetts Eric Wilcots University of Wisconsin Christine Wilson McMaster University

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Appendix D

The NRAO Visiting Committee

The NRAO Visiting Committee is appointed by the AUI Board of Trustees to review the management and research programs of the Observatory. The Visiting Committee met in Green Bank in 2002, in Socorro in 2003 and 2004, and will meet in Charlottesville in 2005. Current membership of the Committee is:

George K. Miley, Chair Leiden Observatory Philip Diamond Jodrell Bank Observatory Philip R. Schwartz Aerospace Corporation Eric M. Wilcots University of Wisconsin Roger D. Blandford Stanford Linear Accelerator Center Roger J. V. Brissenden Smithsonian Astrophysical Observatory John E. Carlstrom University of Chicago Rodger Doxsey Space Telescope Science Institute Paul T. P. Ho Harvard-Smithsonian Center for Astrophysics Reinhard Genzel Max Planck Institute for Extraterrestrial Physics Douglas Lin University of California, Santa Cruz Jonas Zmuidzinas G. W. Downs Laboratory of Physics

ALMA Scientific Advisory Committee (ASAC)

The Atacama Large Millimeter Array (ALMA) project has formed a committee to provide scientific advice to the project and outreach to the wider community. Current membership of the Committee is:

Peter Schilke, Chair Max-Planck Institut fur Radioastronomie Jean Turner, Vice Chair University of California, Los Angeles Chris Carilli National Radio Astronomy Observatory Pierre Cox Institut d'Astrophysique Spatiale Yasuo Fukui Nagoya University Diego Mardones University of Chile Munetake Momose Institute of Astrophysics and Planetary Sciences Lee Mundy University of Maryland John Richer MRAO - Cavendish Laboratory Leonardo Testi Arcetri Observatory Ewine van Dishoeck University of Leiden Christine Wilson McMaster University Thomas L. Wilson, ex officio European Southern Observatory Al Wootten, ex officio National Radio Astronomy Observatory Satoshi Yamamoto University of Tokyo

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Appendix D

ALMA Management Advisory Committee (AMAC)

The AMAC was formed to provide advice on the major issues presented to it by the ALMA Board regarding the technical program, cost, and management of the ALMA project, including the management of specific tasks and resources. The AMAC is informed of all progress and developments that occur in the project through periodic reports and briefings. AMAC Committee members are drawn from a wide variety of international scientific institutions, and their expertise and recommendations provide invaluable guidance and direction. Current membership of the Committee is:

Gordon Chin, Chair NASA Goddard Space Flight Center Robert Aymar CERN Sergio Bertini INTEMA Robert Dickman National Science Foundation Janet Fender United States Air Force, Langley Jesús Sánchez Miñana Universidad Politécnica de Madrid Gary Sanders California Institute of Technology Joachim Truemper Max-Planck Institut für Extraterrestrische Physik Arnold Van Ardenne Netherlands Foundation for Research in Astronomy Robert Wilson Harvard-Smithsonian Center for Astrophysics

ALMA North American Science Advisory Committee (ANASAC)

The ANASAC provides scientific advice to the operation of the North American ALMA Science Center as representatives of the wider North American astronomical community. Current membership of the Committee is:

Min Yun, Chair University Massachusetts, Amherst Andrew Blain Caltech Chris Carilli National Radio Astronomy Observatory Richard Crutcher University Illinois Xiaohui Fan University Arizona Jason Glenn University Colorado Mark Gurwell Harvard-Smithsonian Center for Astrophysics David Hollenbach NASA-Ames Research Center Dan Jaffe University Texas Doug Johnstone NRC Canada Lee Mundy University Maryland Phil Myers Harvard-Smithsonian Center for Astrophysics Joan Najita National Optical Astronomy Observatory Luis Rodriguez UNAM Dave Sanders University Hawaii Jean Turner UCLA Christine Wilson McMaster University

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Appendix D

Observatory Computing Council (OCC)

To help engage the entire Observatory in confronting current and future NRAO computing needs, the Observatory Computing Council (OCC), an Observatory-wide group of computing experts and users knowledgeable about computing, was formed to advise the NRAO Director. Current membership of the Committee is:

Bill Cotton, Chair Barry Clark Ed Fomalont Brian Glendenning Eric Greisen Gareth Hunt Joe McMullin Nicole Radziwill Doug Tody Mel Wright

Observatory Science Council (OSC)

The OSC advises the Director on policy issues related to science and academic affairs at the NRAO. Specific issues include: the policies and activities of the Division of Science and Academic Affairs; the review of ideas for new telescopes, projects, instrumentation; and the organization of research support for the scientific staff. Current membership of the Committee is:

Miller Goss, Chair Fred Lo Claire Chandler Jim Condon Dale Frail Dave Hogg Ken Kellermann Jay Lockman Frazer Owen

NRAO Program Plan ♦ FY2005 212

Appendix D

Observatory Technical Council (OTC)

The Observatory Technical Council advises the NRAO Director on technical issues that confront the Observatory, and provides Observatory-wide perspective and coordination in all technical areas, including future planning, research and development, current operations, and projects such as the EVLA and ALMA. Current membership of the Committee is:

D. Emerson, Chair B. Clark R. Fisher B. Glendenning A. Kerr P. Napier J. Payne A. Symmes R. Sramek A. R. Thompson J. Webber

NRAO Program Plan ♦ FY2005 213